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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 JlQRksiK08GIjNz7NizWWO/lD0kYgebZ3Ci3aX0pvetXbqNlstIa6dUkRlXChBo5
 0UDVGe/C7ZFyAlhaz2OTig==

<SEC-DOCUMENT>0001237899-07-000017.txt : 20070227
<SEC-HEADER>0001237899-07-000017.hdr.sgml : 20070227
<ACCEPTANCE-DATETIME>20070227135530
ACCESSION NUMBER:		0001237899-07-000017
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070226
FILED AS OF DATE:		20070227
DATE AS OF CHANGE:		20070227

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Terifay Robert J
		CENTRAL INDEX KEY:			0001391382

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19034
		FILM NUMBER:		07652510

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		914-345-7400

	MAIL ADDRESS:	
		STREET 1:		REGENERON PHARMACEUTICALS, INC.
		STREET 2:		777 OLD SAW MILL RIVER ROAD
		CITY:			TARRYTOWN
		STATE:			NY
		ZIP:			10591
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2007-02-26</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001391382</rptOwnerCik>
            <rptOwnerName>Terifay Robert J</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, Commercial</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>/s/**Robert J. Terifay</signatureName>
        <signatureDate>2007-02-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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