<SEC-DOCUMENT>0001104659-14-023164.txt : 20140327
<SEC-HEADER>0001104659-14-023164.hdr.sgml : 20140327
<ACCEPTANCE-DATETIME>20140327105646
ACCESSION NUMBER:		0001104659-14-023164
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140325
FILED AS OF DATE:		20140327
DATE AS OF CHANGE:		20140327

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALNYLAM PHARMACEUTICALS, INC.
		CENTRAL INDEX KEY:			0001178670
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				770602661
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		300 THIRD STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		(617) 551-8200

	MAIL ADDRESS:	
		STREET 1:		300 THIRD STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALNYLAM PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	20020724

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sanofi
		CENTRAL INDEX KEY:			0001121404
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		STATE OF INCORPORATION:			I0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-50743
		FILM NUMBER:		14720568

	BUSINESS ADDRESS:	
		STREET 1:		54 RUE LA BOETIE
		CITY:			PARIS
		STATE:			I0
		ZIP:			75008
		BUSINESS PHONE:		33153774400

	MAIL ADDRESS:	
		STREET 1:		54 RUE LA BOETIE
		CITY:			PARIS
		STATE:			I0
		ZIP:			75008

	FORMER NAME:	
		FORMER CONFORMED NAME:	SANOFI-AVENTIS
		DATE OF NAME CHANGE:	20040826

	FORMER NAME:	
		FORMER CONFORMED NAME:	SANOFI SYNTHELABO SA
		DATE OF NAME CHANGE:	20010104
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-03-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001178670</issuerCik>
        <issuerName>ALNYLAM PHARMACEUTICALS, INC.</issuerName>
        <issuerTradingSymbol>ALNY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001121404</rptOwnerCik>
            <rptOwnerName>Sanofi</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>54 RUE LA BOETIE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PARIS</rptOwnerCity>
            <rptOwnerState>I0</rptOwnerState>
            <rptOwnerZipCode>75008</rptOwnerZipCode>
            <rptOwnerStateDescription>FRANCE</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-03-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>344448</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>66.88</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9110786</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>VIA WHOLLY-OWNED SUBSIDIARY, GENZYME CORP.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <remarks>Purchase of shares in accordance with the terms of the investor agreement between Alnylam and Genzyme (a Sanofi company) dated January 11, 2014.</remarks>

    <ownerSignature>
        <signatureName>John Felitti	 Associate Vice President, Corporate Law, Financial &amp; Securities Law</signatureName>
        <signatureDate>2014-03-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
