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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 MeU29SGle/rugWa+UYaxGQ6/xxZkbwzjhFrUwsSOCch9gwgpef0kdo1M/yetUQMh
 iFncUc/9IAC0e+rvREbV1w==

<SEC-DOCUMENT>0001237899-10-000063.txt : 20101221
<SEC-HEADER>0001237899-10-000063.hdr.sgml : 20101221
<ACCEPTANCE-DATETIME>20101221160900
ACCESSION NUMBER:		0001237899-10-000063
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101214
FILED AS OF DATE:		20101221
DATE AS OF CHANGE:		20101221

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STAHL NEIL
		CENTRAL INDEX KEY:			0001226689

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19034
		FILM NUMBER:		101265833

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			REGENERON PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000872589
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				133444607
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		777 OLD SAW MILL RIVER RD
		CITY:			TARRYTOWN
		STATE:			NY
		ZIP:			10591-6707
		BUSINESS PHONE:		9143477000
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2010-12-14</periodOfReport>

    <dateOfOriginalSubmission>2010-12-20</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000872589</issuerCik>
        <issuerName>REGENERON PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>REGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001226689</rptOwnerCik>
            <rptOwnerName>STAHL NEIL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>777 OLD SAW MILL RIVER ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TARRYTOWN</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10591</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP Res and Dev Sciences</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50350</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Award of Restricted Stock under the 2000 Long-Term Incentive Plan that vests in three equal annual installments, commencing one year after the date of grant.</footnote>
        <footnote id="F2">This award was omitted from the reporting person's original Form 4.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stahl, Neil</signatureName>
        <signatureDate>2010-12-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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