<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2009-11-06</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001473597</issuerCik>
        <issuerName>STR Holdings, Inc.</issuerName>
        <issuerTradingSymbol>STRI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001445201</rptOwnerCik>
            <rptOwnerName>Metakis Jason L.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10 WATER STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ENFIELD</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06082</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19802971</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By DLJ Merchant Banking Partners, IV, L.P. and its affiliated funds</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person is an affiliate of DLJ Merchant Banking Partners IV, L.P. and its affiliated funds.  The reporting person disclaims beneficial ownership of these securities, expect to the extent of his pecuniary interests therein.</footnote>
        <footnote id="F2">Includes shares held by DLJ Merchant Banking Partners IV, L.P., DLJ Offshore Partners IV, L.P., DLJ Merchant Banking Partners IV (Pacific), L.P. and MBP IV Plan Investors, L.P.</footnote>
    </footnotes>

    <remarks>See Exhibit 24 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Joseph C. Radziewicz, Attorney-in-fact</signatureName>
        <signatureDate>2009-11-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
