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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-05-16</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000891178</issuerCik>
        <issuerName>EPICOR SOFTWARE CORP</issuerName>
        <issuerTradingSymbol>EPIC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000905980</rptOwnerCik>
            <rptOwnerName>PICKUP RICHARD H/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O EPICOR SOFTWARE CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>18200 VON KARMAN AVENUE, SUITE 1000</rptOwnerStreet2>
            <rptOwnerCity>IRVINE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92612</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3608903</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.5</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Disposed of pursuant to merger agreement between issuer and Element Merger Sub in exchange for $12.50 per share.</footnote>
        <footnote id="F2">Consisted of (i) 70,000 shares owned directly by Mr. Pickup; (ii) 502,300 shares owned directly by Pickup Family Trust and 400,000 shares owned directly by TB Funds, LLC, over all of which shares Mr. Pickup has sole investment and voting power; (iii) 900 shares owned directly by Gamebusters Inc., 1,350,000 shares owned directly by Dito Caree LP, 885,000 shares owned directly by Dito Devcar LP, 182,257 shares owned directly by Pickup CRUT II and 95,600 shares owned directly by Pickup CRUT I, over all of which shares Mr. Pickup has shared investment and voting power; and (iv) 20,000 shares owned directly by Dito Devcar Foundation.  100,000 shares owned by Carole Pickup, Mr. Pickup's spouse, over which Mr. Pickup is deemed to have shared investment and voting power were tendered in the transaction for $12.50 per share. Mr. Pickup disclaims beneficial ownership of the shares owned by his spouse.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/John D. Ireland, Attorney in Fact</signatureName>
        <signatureDate>2011-05-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
