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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-03-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000912908</issuerCik>
        <issuerName>FOAMEX INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>FMXL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263972</rptOwnerCik>
            <rptOwnerName>D. E. SHAW LAMINAR PORTFOLIOS, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>39TH FLOOR, TOWER 45</rptOwnerStreet1>
            <rptOwnerStreet2>120 WEST FORTY-FIFTH STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>See Footnotes 4 and 5.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001009268</rptOwnerCik>
            <rptOwnerName>D. E. SHAW &amp; CO, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>39TH FLOOR, TOWER 45</rptOwnerStreet1>
            <rptOwnerStreet2>120 WEST FORTY-FIFTH STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>See Footnotes 4 and 5.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001277502</rptOwnerCik>
            <rptOwnerName>D. E. SHAW &amp; CO, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>39TH FLOOR, TOWER 45</rptOwnerStreet1>
            <rptOwnerStreet2>120 WEST FORTY-FIFTH STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>See Footnotes 4 and 5.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001023870</rptOwnerCik>
            <rptOwnerName>SHAW DAVID E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>39TH FLOOR, TOWER 45</rptOwnerStreet1>
            <rptOwnerStreet2>120 WEST FORTY-FIFTH STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>See Footnotes 4 and 5.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-03-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16092</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5740898</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.11</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-03-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12081</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-03-01</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-03-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12081</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12081</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Issued by Issuer in a transaction exempt under Rule 16(b)(3) to D. E. Shaw &amp; Co., L.P. (&quot;DESCO LP&quot;), Seth Charnow's employer, as compensation for Seth Charnow's service as a director of the Issuer (see Footnote 5).  No separate consideration was paid for the security.</footnote>
        <footnote id="F2">Amount of Common Stock issued based on dividing $46,666 (the amount of annual stock-based compensation for Directors, excluding stock options) by the 30 trading day average price of the Issuer's common stock for the period ended February 22, 2008.</footnote>
        <footnote id="F3">Options vest in four equal annual installments beginning on the first anniversary of the date of grant.</footnote>
        <footnote id="F4">DESCO LP, as an investment adviser to D. E. Shaw Laminar Portfolios, L.L.C. (&quot;Laminar&quot;); D. E. Shaw &amp; Co., L.L.C. (&quot;DESCO LLC&quot;), as managing member of Laminar; and Mr. David E. Shaw (&quot;David E. Shaw&quot;) (as president and sole shareholder of D. E. Shaw  &amp; Co., Inc., which is the general partner of DESCO LP, and as president and sole shareholder of D. E. Shaw &amp; Co. II, Inc., which is the managing member of DESCO LLC) may be deemed to be the beneficial owners of more than 10% of the Common Stock of the Issuer for purposes of Rule 16a-1(a) of the Securities Exchange Act of 1934.</footnote>
        <footnote id="F5">(Continued from Footnote 4)  In accordance with instruction 4(b)(iv), the entire amount of securities of the issuer that may be deemed to be beneficially owned by DESCO LP, DESCO LLC, or Laminar is reported herein.  Each of DESCO LP, DESCO LLC, and David E. Shaw disclaims any beneficial ownership of any of the securities listed in this Form 4, except to the extent of any pecuniary interest therein.  The reporting persons also may be deemed, for Section 16 purposes, directors of the Issuer by virtue of DESCO LP employee Seth Charnow's service as a member of the Issuer's board of directors.  None of Laminar, DESCO LP, DESCO LLC, or David E. Shaw serves as a director of the Issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>D. E. Shaw Laminar Portfolios, L.L.C. By: D. E. Shaw &amp; Co., L.L.C., as managing member By: /s/ Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>D. E. Shaw &amp; Co., L.P. By: /s/ Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>D. E. Shaw &amp; Co., L.L.C. By: /s/ Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>David E. Shaw By: /s/ Rochelle Elias, Attorney-in-Fact for David E. Shaw</signatureName>
        <signatureDate>2008-03-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
