<SEC-DOCUMENT>0001250853-17-000069.txt : 20170808
<SEC-HEADER>0001250853-17-000069.hdr.sgml : 20170808
<ACCEPTANCE-DATETIME>20170808142913
ACCESSION NUMBER:		0001250853-17-000069
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170801
FILED AS OF DATE:		20170808
DATE AS OF CHANGE:		20170808

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			EDDLEMAN ROY T
		CENTRAL INDEX KEY:			0001270264

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		171014283

	MAIL ADDRESS:	
		STREET 1:		110 W. GEORGE BURNS ROAD
		STREET 2:		SUITE D-4018
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90048

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			REPLIGEN CORP
		CENTRAL INDEX KEY:			0000730272
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				042729386
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453
		BUSINESS PHONE:		7814499560

	MAIL ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2017-08-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000730272</issuerCik>
        <issuerName>REPLIGEN CORP</issuerName>
        <issuerTradingSymbol>RGEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001270264</rptOwnerCik>
            <rptOwnerName>EDDLEMAN ROY T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>417 AMAPOLA LANE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90077</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common stock, $.01 par value</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4782344</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 357,518 shares held for the reporting person's benefit in a 15-month escrow established in connection with the August 1, 2017 merger acquisition by Repligen Corporation of Spectrum, Inc.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Istvan Benko, Attorney-in-fact for Roy T. Eddleman</signatureName>
        <signatureDate>2017-08-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
