<XBRL>
<?xml version="1.0" encoding="us-ascii"?>
<!--XBRL document created with Crossfire by Rivet Software version 4.3.96.0 http://www.rivetsoftware.com-->
<!--Based on XBRL 2.1-->
<!--Created on: 3/14/2012 4:20:29 PM-->
<!--Modified on: 3/14/2012 4:20:30 PM-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#StatementConsolidatedStatementsOfShareholdersEquity" roleURI="http://www.questcor.com/2011-06-30/role/StatementConsolidatedStatementsOfShareholdersEquity" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesTables" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesTables" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosurePreferredStockAndShareholdersEquityTables" roleURI="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityTables" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfAccountsReceivableDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfAccountsReceivableDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfGrossProductSalesDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfGrossProductSalesDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNetSalesDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNetSalesDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailss" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailss" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailsss" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailsss" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureBalanceSheetDetailsPropertyAndEquipmentDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureBalanceSheetDetailsPropertyAndEquipmentDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureShortTermInvestmentsAndFairValueMeasurementsNarrativeDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsNarrativeDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureShortTermInvestmentsAndFairValueMeasurementsSummaryOfCashEquivalentsAndShortTermInvestmentsDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsSummaryOfCashEquivalentsAndShortTermInvestmentsDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureShortTermInvestmentsAndFairValueMeasurementsAvailableForSaleSecuritiesInUnrealizedLossPositionNotDeemedToBeOtherThanTemporarilyImpairedDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsAvailableForSaleSecuritiesInUnrealizedLossPositionNotDeemedToBeOtherThanTemporarilyImpairedDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureShortTermInvestmentsAndFairValueMeasurementsAssetsMeasuredAtFairValueOnRecurringBasisDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsAssetsMeasuredAtFairValueOnRecurringBasisDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosurePreferredStockAndShareholdersEquityNarrativeDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityNarrativeDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetailss" roleURI="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetailss" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosurePreferredStockAndShareholdersEquityShareBasedCompensationExpenseDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityShareBasedCompensationExpenseDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#DisclosureIncomeTaxesNarrativeDetails" roleURI="http://www.questcor.com/2011-06-30/role/DisclosureIncomeTaxesNarrativeDetails" />
  <roleRef xlink:type="simple" xlink:href="qcor-20111231.xsd#ScheduleScheduleIiValuationAndQualifyingAccountsValuationAndQualifyingAccountsDetails" roleURI="http://www.questcor.com/2011-06-30/role/ScheduleScheduleIiValuationAndQualifyingAccountsValuationAndQualifyingAccountsDetails" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/StatementConsolidatedStatementsOfShareholdersEquity" xlink:type="extended" xlink:title="00300 - Statement - Consolidated Statements Of Shareholders' Equity">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_634673388258672240" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain_634673388258672240" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ParentMember" xlink:label="us-gaap_ParentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_ParentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ParentMember" xlink:to="us-gaap_CommonStockMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_ParentMember" xlink:to="us-gaap_RetainedEarningsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_ParentMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquity" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="us-gaap_CommonStockSharesOutstanding" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockSharesOutstanding" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedToConsultantsAndEmployees" xlink:label="qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedToConsultantsAndEmployees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedToConsultantsAndEmployees" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedSharesToConsultantsAndEmployees" xlink:label="qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedSharesToConsultantsAndEmployees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockCompensationForEquityIncentivesAndRestrictedCommonStockGrantedSharesToConsultantsAndEmployees" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="us-gaap_StockRepurchasedDuringPeriodValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="us-gaap_StockRepurchasedDuringPeriodShares" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchasedDuringPeriodShares" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CancellationOfSharesRelatedToTaxLiability" xlink:label="qcor_CancellationOfSharesRelatedToTaxLiability" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CancellationOfSharesRelatedToTaxLiability" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:to="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:to="us-gaap_NetIncomeLoss" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="extended" xlink:title="30103 - Disclosure - Organization and Summary Of Significant Accounting Policies (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain_634673388258828239" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain_634673388258828239" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TricareMember" xlink:label="qcor_TricareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_TricareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_RelativeShareOfAccountsReceivableTableTextBlock" xlink:label="qcor_RelativeShareOfAccountsReceivableTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_RelativeShareOfAccountsReceivableTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_RelativeShareOfGrossProductSalesTableTextBlock" xlink:label="qcor_RelativeShareOfGrossProductSalesTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_RelativeShareOfGrossProductSalesTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_NetSalesTableTextBlock" xlink:label="qcor_NetSalesTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_NetSalesTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_SalesRelatedReservesTableTextBlock" xlink:label="qcor_SalesRelatedReservesTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_SalesRelatedReservesTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActivityInAccountForSalesRelatedReservesTableTextBlock" xlink:label="qcor_ActivityInAccountForSalesRelatedReservesTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ActivityInAccountForSalesRelatedReservesTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_AmountsExcludedFromComputationOfDilutedNetIncomePerShareApplicableToCommonShareholderTableTextBlock" xlink:label="qcor_AmountsExcludedFromComputationOfDilutedNetIncomePerShareApplicableToCommonShareholderTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_AmountsExcludedFromComputationOfDilutedNetIncomePerShareApplicableToCommonShareholderTableTextBlock" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityTables" xlink:type="extended" xlink:title="30503 - Disclosure - Preferred Stock And Shareholders' Equity (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_634673388258828239" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_634673388258828239" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanMember" xlink:label="qcor_EmployeeStockPurchasePlanMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="qcor_EmployeeStockPurchasePlanMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="us-gaap_StockOptionsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="us-gaap_StockOptionsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationEmployeeStockPurchasePlanActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationEmployeeStockPurchasePlanActivityTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationEmployeeStockPurchasePlanActivityTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValueTableTextBlock" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValueTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValueTableTextBlock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:label="us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" xlink:title="40101 - Disclosure - Organization And Summary Of Significant Accounting Policies (Narrative) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="us-gaap_ProductOrServiceAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ProductOrServiceAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="us-gaap_ProductsAndServicesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductsAndServicesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="us-gaap_ProductsAndServicesDomain_634673388258828239" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductsAndServicesDomain_634673388258828239" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MultipleSclerosisAndNephroticSyndromeMember" xlink:label="qcor_MultipleSclerosisAndNephroticSyndromeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="qcor_MultipleSclerosisAndNephroticSyndromeMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActharMember" xlink:label="qcor_ActharMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="qcor_ActharMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember_634673388258828239" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember_634673388258828239" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PreviousMember" xlink:label="qcor_PreviousMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_RangeMember" xlink:to="qcor_PreviousMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_AsAmendedMember" xlink:label="qcor_AsAmendedMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_RangeMember" xlink:to="qcor_AsAmendedMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ReductionMember" xlink:label="qcor_ReductionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_RangeMember" xlink:to="qcor_ReductionMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="3" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MedicaidMember" xlink:label="qcor_MedicaidMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_MedicaidMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TricareMember" xlink:label="qcor_TricareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_TricareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MedicareMember" xlink:label="qcor_MedicareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_MedicareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_VeteransAdministrationMember" xlink:label="qcor_VeteransAdministrationMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_VeteransAdministrationMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurascriptSdMember" xlink:label="qcor_CurascriptSdMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_CurascriptSdMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_NumberOfIndicationsThatAreApprovedForTreatment" xlink:label="qcor_NumberOfIndicationsThatAreApprovedForTreatment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_NumberOfIndicationsThatAreApprovedForTreatment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_NumberOfIndicationsThatGenerateSubstantiallyAllOfNetSales" xlink:label="qcor_NumberOfIndicationsThatGenerateSubstantiallyAllOfNetSales" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_NumberOfIndicationsThatGenerateSubstantiallyAllOfNetSales" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MaximumTreatmentAgeOfInfantileSpasms" xlink:label="qcor_MaximumTreatmentAgeOfInfantileSpasms" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_MaximumTreatmentAgeOfInfantileSpasms" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_FreeDrugsValueContributed" xlink:label="qcor_FreeDrugsValueContributed" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_FreeDrugsValueContributed" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLifeMinimum" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLifeMinimum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLifeMinimum" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLifeMaximum" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLifeMaximum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLifeMaximum" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiability" xlink:label="us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiability" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiability" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_NumberOfSpecialtyPharmaciesThatDistribute" xlink:label="qcor_NumberOfSpecialtyPharmaciesThatDistribute" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_NumberOfSpecialtyPharmaciesThatDistribute" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_RebateAmountAsPercentageOfAverageManufacturerPrice" xlink:label="qcor_RebateAmountAsPercentageOfAverageManufacturerPrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_RebateAmountAsPercentageOfAverageManufacturerPrice" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_DaysAfterQuarterRebateInvoicesReceived" xlink:label="qcor_DaysAfterQuarterRebateInvoicesReceived" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_DaysAfterQuarterRebateInvoicesReceived" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PercentageOfSales" xlink:label="qcor_PercentageOfSales" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_PercentageOfSales" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_SalesReserveForRebates" xlink:label="qcor_SalesReserveForRebates" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="16" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_SalesReserveForRebates" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PercentageOfEstimatedLiabilityCoveredBySalesReserve" xlink:label="qcor_PercentageOfEstimatedLiabilityCoveredBySalesReserve" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="17" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_PercentageOfEstimatedLiabilityCoveredBySalesReserve" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_RebatePerVial" xlink:label="qcor_RebatePerVial" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="18" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_RebatePerVial" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PaymentTermsDays" xlink:label="qcor_PaymentTermsDays" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="19" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_PaymentTermsDays" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_UnrecognizedCompensationCostErlatedToUnvestedStockOptions" xlink:label="qcor_UnrecognizedCompensationCostErlatedToUnvestedStockOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="20" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_UnrecognizedCompensationCostErlatedToUnvestedStockOptions" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="21" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfAccountsReceivableDetails" xlink:type="extended" xlink:title="40102 - Disclosure - Organization And Summary Of Significant Accounting Policies (Relative Share Of Accounts Receivable ) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurascriptSdMember" xlink:label="qcor_CurascriptSdMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_CurascriptSdMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_OtherCustomersMember" xlink:label="qcor_OtherCustomersMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_OtherCustomersMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PercentageOfAccountsReceivable" xlink:label="qcor_PercentageOfAccountsReceivable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_PercentageOfAccountsReceivable" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesRelativeShareOfGrossProductSalesDetails" xlink:type="extended" xlink:title="40103 - Disclosure - Organization And Summary Of Significant Accounting Policies (Relative Share Of Gross Product Sales ) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurascriptSdMember" xlink:label="qcor_CurascriptSdMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_CurascriptSdMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_OtherCustomersMember" xlink:label="qcor_OtherCustomersMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_OtherCustomersMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PercentageOfGrossProductSales" xlink:label="qcor_PercentageOfGrossProductSales" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_PercentageOfGrossProductSales" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesNetSalesDetails" xlink:type="extended" xlink:title="40104 - Disclosure - Organization And Summary Of Significant Accounting Policies (Net Sales) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MedicaidMember" xlink:label="qcor_MedicaidMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_MedicaidMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CoverageGapDiscountProgramMember" xlink:label="qcor_CoverageGapDiscountProgramMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_CoverageGapDiscountProgramMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TricareMember" xlink:label="qcor_TricareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_TricareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SalesRevenueGoodsGross" xlink:label="us-gaap_SalesRevenueGoodsGross" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SalesRevenueGoodsGross" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ProvisionForRebatesDiscounts" xlink:label="qcor_ProvisionForRebatesDiscounts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ProvisionForRebatesDiscounts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ProvisionForChargebacks" xlink:label="qcor_ProvisionForChargebacks" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ProvisionForChargebacks" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CoPaymentAssistanceAndOther" xlink:label="qcor_CoPaymentAssistanceAndOther" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CoPaymentAssistanceAndOther" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TotalSalesReserves" xlink:label="qcor_TotalSalesReserves" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_TotalSalesReserves" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="us-gaap_SalesRevenueNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SalesRevenueNet" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetails" xlink:type="extended" xlink:title="40105 - Disclosure - Organization And Summary Of Significant Accounting Policies (Sales-Related Reserves) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MedicaidMember" xlink:label="qcor_MedicaidMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_MedicaidMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TricareMember" xlink:label="qcor_TricareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_TricareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CoverageGapDiscountProgramMember" xlink:label="qcor_CoverageGapDiscountProgramMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_CoverageGapDiscountProgramMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_Rebates" xlink:label="qcor_Rebates" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_Rebates" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_GovernmentChargebacks" xlink:label="qcor_GovernmentChargebacks" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_GovernmentChargebacks" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_OtherDiscounts" xlink:label="qcor_OtherDiscounts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_OtherDiscounts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_SalesReserves" xlink:label="qcor_SalesReserves" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_SalesReserves" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailss" xlink:type="extended" xlink:title="40106 - Disclosure - Organization And Summary Of Significant Accounting Policies (Sales-Related Reserves) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_MedicaidMember" xlink:label="qcor_MedicaidMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_MedicaidMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_Balance" xlink:label="qcor_Balance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_Balance" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActualRebatePaymentsForSalesMadeInPriorYear" xlink:label="qcor_ActualRebatePaymentsForSalesMadeInPriorYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ActualRebatePaymentsForSalesMadeInPriorYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" xlink:label="qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurrentRebateProvisionForSalesMadeInPriorYear" xlink:label="qcor_CurrentRebateProvisionForSalesMadeInPriorYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CurrentRebateProvisionForSalesMadeInPriorYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" xlink:label="qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureOrganizationAndSummaryOfSignificantAccountingPoliciesSalesRelatedReservesDetailsss" xlink:type="extended" xlink:title="40107 - Disclosure - Organization And Summary Of Significant Accounting Policies (Sales-Related Reserves) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="us-gaap_MajorCustomersAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_MajorCustomersAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="us-gaap_NameOfMajorCustomerDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_MajorCustomersAxis" xlink:to="us-gaap_NameOfMajorCustomerDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_TricareMember" xlink:label="qcor_TricareMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_NameOfMajorCustomerDomain" xlink:to="qcor_TricareMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_Balance" xlink:label="qcor_Balance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_Balance" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActualRebatePaymentsForSalesMadeInPriorYear" xlink:label="qcor_ActualRebatePaymentsForSalesMadeInPriorYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ActualRebatePaymentsForSalesMadeInPriorYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" xlink:label="qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ActualRebatePaymentsForSalesMadeInCurrentYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurrentRebateProvisionForSalesMadeInPriorYear" xlink:label="qcor_CurrentRebateProvisionForSalesMadeInPriorYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CurrentRebateProvisionForSalesMadeInPriorYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" xlink:label="qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CurrentRebateProvisionForSalesMadeInCurrentYear" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureBalanceSheetDetailsPropertyAndEquipmentDetails" xlink:type="extended" xlink:title="40203 - Disclosure - Balance Sheet Details (Property And Equipment) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_634673388258984238" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_634673388258984238" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LandAndBuildingMember" xlink:label="us-gaap_LandAndBuildingMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_LandAndBuildingMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_LandAndBuildingMember" xlink:to="us-gaap_LeaseholdImprovementsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="us-gaap_MachineryAndEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_MachineryAndEquipmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_LaboratoryEquipmentMember" xlink:label="qcor_LaboratoryEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_MachineryAndEquipmentMember" xlink:to="qcor_LaboratoryEquipmentMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ManufacturingEquipmentMember" xlink:label="qcor_ManufacturingEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_MachineryAndEquipmentMember" xlink:to="qcor_ManufacturingEquipmentMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OfficeEquipmentMember" xlink:label="us-gaap_OfficeEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_MachineryAndEquipmentMember" xlink:to="us-gaap_OfficeEquipmentMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentGross" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsNarrativeDetails" xlink:type="extended" xlink:title="40301 - Disclosure - Short-Term Investments And Fair Value Measurements (Narrative) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="us-gaap_ProductOrServiceAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ProductOrServiceAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="us-gaap_ProductsAndServicesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductsAndServicesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PriorPeriodTransactionsMember" xlink:label="qcor_PriorPeriodTransactionsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="qcor_PriorPeriodTransactionsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_AverageContractualMaturityOfShortTermInvestmentsInMonths" xlink:label="qcor_AverageContractualMaturityOfShortTermInvestmentsInMonths" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_AverageContractualMaturityOfShortTermInvestmentsInMonths" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_Goodwill" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsSummaryOfCashEquivalentsAndShortTermInvestmentsDetails" xlink:type="extended" xlink:title="40302 - Disclosure - Short-Term Investments And Fair Value Measurements (Summary Of Cash Equivalents And Short-Term Investments) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:label="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain_634673388258984238" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain_634673388258984238" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashEquivalentsMember" xlink:label="us-gaap_CashEquivalentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_CashEquivalentsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="us-gaap_CertificatesOfDepositMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_CertificatesOfDepositMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CorporateBondsMember" xlink:label="qcor_CorporateBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_CorporateBondsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_USGovernmentSponsoredEnterprisesMember" xlink:label="qcor_USGovernmentSponsoredEnterprisesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_USGovernmentSponsoredEnterprisesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="us-gaap_MunicipalBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_MunicipalBondsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CashAndCashEquivalentsFairValueDisclosure" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesFairValueDisclosure" xlink:label="us-gaap_AvailableForSaleSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesFairValueDisclosure" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesAmortizedCost" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:label="us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsAvailableForSaleSecuritiesInUnrealizedLossPositionNotDeemedToBeOtherThanTemporarilyImpairedDetails" xlink:type="extended" xlink:title="40304 - Disclosure - Short-Term Investments And Fair Value Measurements (Available-For-Sale Securities In An Unrealized Loss Position, Not Deemed To Be Other-Than-Temporarily Impaired) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:label="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="us-gaap_CertificatesOfDepositMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_CertificatesOfDepositMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CorporateBondsMember" xlink:label="qcor_CorporateBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_CorporateBondsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_USGovernmentSponsoredEnterprisesMember" xlink:label="qcor_USGovernmentSponsoredEnterprisesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_USGovernmentSponsoredEnterprisesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="us-gaap_MunicipalBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_MunicipalBondsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1" xlink:label="us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1" xlink:label="us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureShortTermInvestmentsAndFairValueMeasurementsAssetsMeasuredAtFairValueOnRecurringBasisDetails" xlink:type="extended" xlink:title="40305 - Disclosure - Short-Term Investments And Fair Value Measurements (Assets Measured At Fair Value On A Recurring Basis) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:label="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashEquivalentsMember" xlink:label="us-gaap_CashEquivalentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_CashEquivalentsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="us-gaap_CertificatesOfDepositMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_CertificatesOfDepositMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CorporateBondsMember" xlink:label="qcor_CorporateBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_CorporateBondsMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_USGovernmentSponsoredEnterprisesMember" xlink:label="qcor_USGovernmentSponsoredEnterprisesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="qcor_USGovernmentSponsoredEnterprisesMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MunicipalBondsMember" xlink:label="us-gaap_MunicipalBondsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="us-gaap_MunicipalBondsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsByMeasurementAxis" xlink:label="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsByMeasurementAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsByMeasurementAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValuePlanAssetMeasurementDomain" xlink:label="us-gaap_FairValuePlanAssetMeasurementDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsByMeasurementAxis" xlink:to="us-gaap_FairValuePlanAssetMeasurementDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValuePlanAssetMeasurementDomain" xlink:label="us-gaap_FairValuePlanAssetMeasurementDomain_634673388258984238" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsByMeasurementAxis" xlink:to="us-gaap_FairValuePlanAssetMeasurementDomain_634673388258984238" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="us-gaap_FairValueInputsLevel1Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_FairValuePlanAssetMeasurementDomain" xlink:to="us-gaap_FairValueInputsLevel1Member" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="us-gaap_FairValueInputsLevel2Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_FairValuePlanAssetMeasurementDomain" xlink:to="us-gaap_FairValueInputsLevel2Member" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="us-gaap_FairValueInputsLevel3Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_FairValuePlanAssetMeasurementDomain" xlink:to="us-gaap_FairValueInputsLevel3Member" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsFairValueDisclosureRecurring" xlink:label="us-gaap_AssetsFairValueDisclosureRecurring" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AssetsFairValueDisclosureRecurring" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityNarrativeDetails" xlink:type="extended" xlink:title="40501 - Disclosure - Preferred Stock And Shareholders' Equity (Narrative) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_PreviousMember" xlink:label="qcor_PreviousMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_RangeMember" xlink:to="qcor_PreviousMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_AsAmendedMember" xlink:label="qcor_AsAmendedMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_RangeMember" xlink:to="qcor_AsAmendedMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityClassOfTreasuryStockAxis" xlink:label="us-gaap_EquityClassOfTreasuryStockAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_EquityClassOfTreasuryStockAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassOfTreasuryStockDomain" xlink:label="us-gaap_ClassOfTreasuryStockDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_EquityClassOfTreasuryStockAxis" xlink:to="us-gaap_ClassOfTreasuryStockDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassOfTreasuryStockDomain" xlink:label="us-gaap_ClassOfTreasuryStockDomain_634673388258984238" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_EquityClassOfTreasuryStockAxis" xlink:to="us-gaap_ClassOfTreasuryStockDomain_634673388258984238" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockRepurchaseProgramMember" xlink:label="qcor_StockRepurchaseProgramMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ClassOfTreasuryStockDomain" xlink:to="qcor_StockRepurchaseProgramMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_OutsideOfStockRepurchaseProgramMember" xlink:label="qcor_OutsideOfStockRepurchaseProgramMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_ClassOfTreasuryStockDomain" xlink:to="qcor_OutsideOfStockRepurchaseProgramMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CumulativeCommonStockRepurchasedMember" xlink:label="qcor_CumulativeCommonStockRepurchasedMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_ClassOfTreasuryStockDomain" xlink:to="qcor_CumulativeCommonStockRepurchasedMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="us-gaap_PreferredStockSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PreferredStockSharesAuthorized" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:label="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_SharesOfCommonStockRepurchased" xlink:label="qcor_SharesOfCommonStockRepurchased" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_SharesOfCommonStockRepurchased" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_PaymentsForRepurchaseOfCommonStock" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:label="us-gaap_TreasuryStockAcquiredAverageCostPerShare" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TreasuryStockAcquiredAverageCostPerShare" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" xlink:label="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchaseProgramSharesAvailableForIssuanceIncludingPreviouslyIssued" xlink:label="qcor_EmployeeStockPurchaseProgramSharesAvailableForIssuanceIncludingPreviouslyIssued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchaseProgramSharesAvailableForIssuanceIncludingPreviouslyIssued" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchaseProgramMaximiumOfferingPeriod" xlink:label="qcor_EmployeeStockPurchaseProgramMaximiumOfferingPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchaseProgramMaximiumOfferingPeriod" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanEligibilityRequirementsHoursWorkedPerWeek" xlink:label="qcor_EmployeeStockPurchasePlanEligibilityRequirementsHoursWorkedPerWeek" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="10" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchasePlanEligibilityRequirementsHoursWorkedPerWeek" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanEligibilityRequirementsMonthsWorkedPerCalendarYear" xlink:label="qcor_EmployeeStockPurchasePlanEligibilityRequirementsMonthsWorkedPerCalendarYear" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="11" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchasePlanEligibilityRequirementsMonthsWorkedPerCalendarYear" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanMaximiumEarningsWithheld" xlink:label="qcor_EmployeeStockPurchasePlanMaximiumEarningsWithheld" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="12" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchasePlanMaximiumEarningsWithheld" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanPurchasePricePerSharePercentageOfFairMarketValue" xlink:label="qcor_EmployeeStockPurchasePlanPurchasePricePerSharePercentageOfFairMarketValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="13" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_EmployeeStockPurchasePlanPurchasePricePerSharePercentageOfFairMarketValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="14" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="15" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsMaximiumTerm" xlink:label="qcor_StockOptionsMaximiumTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="16" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsMaximiumTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsIncreaseOfSharesOfCommonStockAuthorizedForIssuance" xlink:label="qcor_StockOptionsIncreaseOfSharesOfCommonStockAuthorizedForIssuance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="17" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsIncreaseOfSharesOfCommonStockAuthorizedForIssuance" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="18" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsGrantedFollowingAppointmentAsNonEmployeeDirector" xlink:label="qcor_StockOptionsGrantedFollowingAppointmentAsNonEmployeeDirector" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="19" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsGrantedFollowingAppointmentAsNonEmployeeDirector" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsGrantedForContinuedServiceUponReappointment" xlink:label="qcor_StockOptionsGrantedForContinuedServiceUponReappointment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="20" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsGrantedForContinuedServiceUponReappointment" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsGrantedToMembersOfOneOrMoreCommitteesOfBoardOfDirectors" xlink:label="qcor_StockOptionsGrantedToMembersOfOneOrMoreCommitteesOfBoardOfDirectors" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="21" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsGrantedToMembersOfOneOrMoreCommitteesOfBoardOfDirectors" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionsGrantedToChairsOfOneOrMoreCommittees" xlink:label="qcor_StockOptionsGrantedToChairsOfOneOrMoreCommittees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="22" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionsGrantedToChairsOfOneOrMoreCommittees" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_StockOptionGrantExercisePricePercentageOfFairMarketValue" xlink:label="qcor_StockOptionGrantExercisePricePercentageOfFairMarketValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="23" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_StockOptionGrantExercisePricePercentageOfFairMarketValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CommonStockSharesAuthorizedForGrant" xlink:label="qcor_CommonStockSharesAuthorizedForGrant" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="24" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_CommonStockSharesAuthorizedForGrant" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_SharesOfCommonStockReservedForIssuance" xlink:label="qcor_SharesOfCommonStockReservedForIssuance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="25" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_SharesOfCommonStockReservedForIssuance" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="26" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="27" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RestrictedStockExpense" xlink:label="us-gaap_RestrictedStockExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="28" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_RestrictedStockExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RestrictedInvestmentsAtFairValue" xlink:label="us-gaap_RestrictedInvestmentsAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="29" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_RestrictedInvestmentsAtFairValue" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_UnamortizedCompensationCostsRelatedToRestrictedStockAwards" xlink:label="qcor_UnamortizedCompensationCostsRelatedToRestrictedStockAwards" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="30" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_UnamortizedCompensationCostsRelatedToRestrictedStockAwards" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_RestrictedStockVestingPeriod" xlink:label="qcor_RestrictedStockVestingPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="31" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_RestrictedStockVestingPeriod" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="32" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="33" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPayments" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPayments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="34" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendPayments" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetailss" xlink:type="extended" xlink:title="40503 - Disclosure - Preferred Stock And Shareholders' Equity (Stock Option Valuation Assumption) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_EmployeeStockPurchasePlanMember" xlink:label="qcor_EmployeeStockPurchasePlanMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="qcor_EmployeeStockPurchasePlanMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityStockOptionValuationAssumptionDetails" xlink:type="extended" xlink:title="40507 - Disclosure - Preferred Stock And Shareholders' Equity (Stock Option Valuation Assumption) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="us-gaap_StockOptionsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="us-gaap_StockOptionsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="us-gaap_RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="2" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_RangeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="us-gaap_RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MaximumMember" xlink:label="us-gaap_MaximumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinimumMember" xlink:label="us-gaap_MinimumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_ForfeitureRate" xlink:label="qcor_ForfeitureRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_ForfeitureRate" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosurePreferredStockAndShareholdersEquityShareBasedCompensationExpenseDetails" xlink:type="extended" xlink:title="40508 - Disclosure - Preferred Stock And Shareholders' Equity (Share-Based Compensation Expense) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_634673388259140237" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsByReportLineAxis" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain_634673388259140237" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="us-gaap_SellingAndMarketingExpenseMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:to="us-gaap_SellingAndMarketingExpenseMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:to="us-gaap_GeneralAndAdministrativeExpenseMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsReportLineDomain" xlink:to="us-gaap_ResearchAndDevelopmentExpenseMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/DisclosureIncomeTaxesNarrativeDetails" xlink:type="extended" xlink:title="40701 - Disclosure - Income Taxes (Narrative) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="us-gaap_IncomeTaxAuthorityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_IncomeTaxAuthorityAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain_634673388259296236" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain_634673388259296236" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_FederalMember" xlink:label="qcor_FederalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="qcor_FederalMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="us-gaap_StateAndLocalJurisdictionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_StateAndLocalJurisdictionMember" use="optional" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_CaliforniaMember" xlink:label="qcor_CaliforniaMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="qcor_CaliforniaMember" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="qcor-20111231.xsd#qcor_DeductionOfTaxableIncomeDueToInternalRevenueCodePercentage" xlink:label="qcor_DeductionOfTaxableIncomeDueToInternalRevenueCodePercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="qcor_DeductionOfTaxableIncomeDueToInternalRevenueCodePercentage" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="us-gaap_OperatingLossCarryforwards" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OperatingLossCarryforwards" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="5" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="6" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_IncomeTaxExpenseBenefit" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="7" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="8" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="us-gaap_UnrecognizedTaxBenefits" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="9" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefits" priority="1" use="optional" />
  </definitionLink>
  <definitionLink xlink:role="http://www.questcor.com/2011-06-30/role/ScheduleScheduleIiValuationAndQualifyingAccountsValuationAndQualifyingAccountsDetails" xlink:type="extended" xlink:title="41001 - Schedule - Schedule II Valuation And Qualifying Accounts (Valuation And Qualifying Accounts) (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="us-gaap_ValuationAllowancesAndReservesTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" order="1" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_ValuationAllowancesAndReservesTypeAxis" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="us-gaap_ValuationAllowancesAndReservesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" order="1" xlink:from="us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:to="us-gaap_ValuationAllowancesAndReservesDomain" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="us-gaap_ValuationAllowancesAndReservesDomain_634673388259296236" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" order="1" xlink:from="us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:to="us-gaap_ValuationAllowancesAndReservesDomain_634673388259296236" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsMember" xlink:label="us-gaap_AllowanceForDoubtfulAccountsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="1" xlink:from="us-gaap_ValuationAllowancesAndReservesDomain" xlink:to="us-gaap_AllowanceForDoubtfulAccountsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InventoryValuationReserveMember" xlink:label="us-gaap_InventoryValuationReserveMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_ValuationAllowancesAndReservesDomain" xlink:to="us-gaap_InventoryValuationReserveMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AllowanceForSalesReturnsMember" xlink:label="us-gaap_AllowanceForSalesReturnsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_ValuationAllowancesAndReservesDomain" xlink:to="us-gaap_AllowanceForSalesReturnsMember" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" order="1" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:label="us-gaap_ValuationAllowancesAndReservesBalance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="2" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesBalance" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:label="us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="3" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" priority="1" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions" xlink:label="us-gaap_ValuationAllowancesAndReservesDeductions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" order="4" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesDeductions" priority="1" use="optional" />
  </definitionLink>
</linkbase>
</XBRL>
