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  <xs:element id="regn_PercentageOfRepaymentOfDevelopmentBalanceOutOfProfits" abstract="false" name="PercentageOfRepaymentOfDevelopmentBalanceOutOfProfits" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_SanofiCollaborationAgreementAntibodyMember" abstract="true" name="SanofiCollaborationAgreementAntibodyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CelltrionIncMember" abstract="true" name="CelltrionIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CollaborativeArrangementUpfrontPaymentMade" abstract="false" name="CollaborativeArrangementUpfrontPaymentMade" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_Amgenv.s.RegeneronMember" abstract="true" name="Amgenv.s.RegeneronMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_A338PatentAnd069PatentMember" abstract="true" name="A338PatentAnd069PatentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CollaborationRevenueMember" abstract="true" name="CollaborationRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AmendedIODiscoveryAgreementMember" abstract="true" name="AmendedIODiscoveryAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_MarketableSecuritiesRealizedLoss" abstract="false" name="MarketableSecuritiesRealizedLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_ThroughDecember312023Member" abstract="true" name="ThroughDecember312023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_A741PatentMember" abstract="true" name="A741PatentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_GrossProductRevenueMember" abstract="true" name="GrossProductRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_SanofiCollaborationAgreementMember" abstract="true" name="SanofiCollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_OtherSalesRelatedDeductionsMember" abstract="true" name="OtherSalesRelatedDeductionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentArrangementContractToPerformForOthersByProductAxis" abstract="true" name="ResearchAndDevelopmentArrangementContractToPerformForOthersByProductAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_AmendedIODiscoveryAgreementBCMAxCD3ProgramMember" abstract="true" name="AmendedIODiscoveryAgreementBCMAxCD3ProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_RegeneronsShareOfCommercialExpensesMember" abstract="true" name="RegeneronsShareOfCommercialExpensesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" abstract="false" name="StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_SalesMilestoneOneMember" abstract="true" name="SalesMilestoneOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_UpfrontPaymentMade" abstract="false" name="UpfrontPaymentMade" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_RestrictedMember" abstract="true" name="RestrictedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_IODiscoveryAgreementMember" abstract="true" name="IODiscoveryAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ExtensionOfResearchTermFee" abstract="false" name="ExtensionOfResearchTermFee" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_StockIssuedDistributedDuringPeriodValueEmployeeBenefitPlan" abstract="false" name="StockIssuedDistributedDuringPeriodValueEmployeeBenefitPlan" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_RevenueRemainingPerformanceObligationVariableConsiderationAmount" abstract="false" name="RevenueRemainingPerformanceObligationVariableConsiderationAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_NumberOfVotesPerShare" abstract="false" name="NumberOfVotesPerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="regn_UnitedStatesGovernmentMember" abstract="true" name="UnitedStatesGovernmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AccrualForSalesRelatedCostsCurrent" abstract="false" name="AccrualForSalesRelatedCostsCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_PraluentCrossLicenseAndCommercializationAgreementMember" abstract="true" name="PraluentCrossLicenseAndCommercializationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ShareOfLossesOutsideUnitedStatesForCollaboratingParty" abstract="false" name="ShareOfLossesOutsideUnitedStatesForCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_ShareRepurchaseProgram2019Member" abstract="true" name="ShareRepurchaseProgram2019Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CollaborativeArrangementAdditionalEligibleAggregatePayments" abstract="false" name="CollaborativeArrangementAdditionalEligibleAggregatePayments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AggregateFutureDevelopmentMilestonePaymentsTheCompanyIsEligibleToReceive" abstract="false" name="AggregateFutureDevelopmentMilestonePaymentsTheCompanyIsEligibleToReceive" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_A226PatentAnd992PatentMember" abstract="true" name="A226PatentAnd992PatentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_RocheCollaborationAgreementMember" abstract="true" name="RocheCollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ArcalystNetProductSalesMember" abstract="true" name="ArcalystNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AccruedClinicalTrialExpenseCurrent" abstract="false" name="AccruedClinicalTrialExpenseCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_AlnylamPharmaceuticalsInc.StockPurchaseAgreementMember" abstract="true" name="AlnylamPharmaceuticalsInc.StockPurchaseAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ClassificationOfInvestmentAxis" abstract="true" name="ClassificationOfInvestmentAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpiration" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardExpiration" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="regn_CollaborationandContractManufacturingMember" abstract="true" name="CollaborationandContractManufacturingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_McKessonCorporationMember" abstract="true" name="McKessonCorporationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_IOAgreementMember" abstract="true" name="IOAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_FinanceLeaseCost" abstract="false" name="FinanceLeaseCost" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_PD1Member" abstract="true" name="PD1Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ShareBasedCompensationArrangementPerformanceThresholdTargetNumberOfAwardsGrantedPercent" abstract="false" name="ShareBasedCompensationArrangementPerformanceThresholdTargetNumberOfAwardsGrantedPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_PraluentNetProductSalesMember" abstract="true" name="PraluentNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_UpFrontAndDevelopmentMilestoneRevenueRecognized" abstract="false" name="UpFrontAndDevelopmentMilestoneRevenueRecognized" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_EffectiveIncomeTaxRateReconciliationSaleOfNonInventoryRelatedAssetsBetweenForeignSubsidiariesPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationSaleOfNonInventoryRelatedAssetsBetweenForeignSubsidiariesPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentArrangementContractToPerformForOthersByProductDomain" abstract="true" name="ResearchAndDevelopmentArrangementContractToPerformForOthersByProductDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AggregatePaymentReceivedWithRegardsToAmendment" abstract="false" name="AggregatePaymentReceivedWithRegardsToAmendment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
