<SEC-DOCUMENT>0001104659-13-069404.txt : 20130912
<SEC-HEADER>0001104659-13-069404.hdr.sgml : 20130912
<ACCEPTANCE-DATETIME>20130912102645
ACCESSION NUMBER:		0001104659-13-069404
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20130911
FILED AS OF DATE:		20130912
DATE AS OF CHANGE:		20130912

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OvaScience, Inc.
		CENTRAL INDEX KEY:			0001544227
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				451472564
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		215 FIRST STREET
		STREET 2:		SUITE 240
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		617-500-2802

	MAIL ADDRESS:	
		STREET 1:		215 FIRST STREET
		STREET 2:		SUITE 240
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Westphal Christoph H
		CENTRAL INDEX KEY:			0001291961

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35890
		FILM NUMBER:		131092927

	MAIL ADDRESS:	
		STREET 1:		C/O ALNYLAM PHARMACEUTICALS, INC
		STREET 2:		300 THIRD STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
</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>2013-09-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001544227</issuerCik>
        <issuerName>OvaScience, Inc.</issuerName>
        <issuerTradingSymbol>OVAS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001291961</rptOwnerCik>
            <rptOwnerName>Westphal Christoph H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OVASCIENCE, INC.,</rptOwnerStreet1>
            <rptOwnerStreet2>215 FIRST STREET, SUITE 240</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02142</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-09-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4850</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.53</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4850</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Christoph H. Westphal Revocable Trust of 2007</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>701927</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3720571</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Longwood Fund, LP</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The trustee of the Christoph H. Westphal Revocable Trust of 2007 is the reporting person and he exercises sole voting and investment power over the shares of record held by the trust.</footnote>
        <footnote id="F2">Longwood Fund GP, LLC is the general partner of Longwood Fund, LP. Voting and investment power with respect to the shares held by Longwood Fund, LP are vested in Richard Aldrich, Michelle Dipp, M.D., Ph.D. and Christoph Westphal, M.D., Ph.D. (collectively, the &quot;Managers&quot;), the managers of Longwood Fund GP, LLC. Each of the Managers disclaims beneficial ownership of the shares held by Longwood Fund, LP, except to the extent of their respective pecuniary interest therein, and the inclusion of these shares in the report shall not be deemed an admission of beneficial ownership of the shares for purposes of Section 16 or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Christopher Bleck, Attorney-in-fact</signatureName>
        <signatureDate>2013-09-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
