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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-07-24</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>120 WEST FORTY-FIFTH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>39TH FLOOR</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 1 and 2.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001009268</rptOwnerCik>
            <rptOwnerName>D. E. SHAW &amp; CO, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>120 WEST FORTY-FIFTH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>39TH FLOOR</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 1 and 2.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001277502</rptOwnerCik>
            <rptOwnerName>D. E. SHAW &amp; CO, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>120 WEST FORTY-FIFTH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>39TH FLOOR</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 1 and 2.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001023870</rptOwnerCik>
            <rptOwnerName>SHAW DAVID E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>120 WEST FORTY-FIFTH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>39TH FLOOR</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 1 and 2.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-07-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18632468</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.525</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>165545712</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series D Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-07-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9661.9515</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">D. E. Shaw &amp; Co., L.P. (&quot;DESCO LP&quot;), as 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 David E. Shaw (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) under the Securities Exchange Act of 1934.</footnote>
        <footnote id="F2">(Continued from Footnote 1) 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 each of DESCO LP employee Seth Charnow's and David Lyon'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>
        <footnote id="F3">On July 24, 2008, Laminar delivered a notice, effective as of July 30, 2008 (the &quot;Conversion Date&quot;), to the Issuer to convert 9,661.9515 shares of Series D Preferred Stock, with an aggregate accrued liquidation preference of $9,782,045.69 as of the Conversion Date, into Common Stock at a conversion price of $0.5250 per share of Common Stock, which will result in the issuance to Laminar of 18,632,468 shares of Common Stock on the Conversion Date.</footnote>
        <footnote id="F4">If the Series D Preferred Stock had been converted within ten days of the consummation of a rights offering that occurred within ninety days of the first issuance of the Series D Preferred Stock, then the price per share of Common Stock received upon conversion of the Series D Preferred Stock would have equaled the price per share of Common Stock in the rights offering, which price was $0.65.  Since this circumstance did not occur, the price per share of Common Stock equaled the average trading price of the Common Stock for the 30-trading-day period ending on the fifth trading day immediately preceding the Conversion Date, which average price was $0.5250.</footnote>
        <footnote id="F5">The Series D Preferred Stock was convertible at any time, at the holder's election, prior to the one-year anniversary of the first date on which shares of the Series D Preferred Stock were issued.</footnote>
        <footnote id="F6">The Series D Preferred Stock had no expiration date.</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: Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-07-28</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>D. E. Shaw &amp; Co. L.P., as managing member By: Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-07-28</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>D. E. Shaw &amp; Co. L.L.C., as managing member By: Rochelle Elias, Chief Compliance Officer</signatureName>
        <signatureDate>2008-07-28</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>David E. Shaw By: Rochelle Elias, Attorney-in-Fact for David E. Shaw</signatureName>
        <signatureDate>2008-07-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
