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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-11-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000897893</issuerCik>
        <issuerName>PEERLESS SYSTEMS CORP</issuerName>
        <issuerTradingSymbol>PRLS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001011938</rptOwnerCik>
            <rptOwnerName>BATHGATE STEVEN MARK</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PEERLESS SYSTEMS CORP</rptOwnerStreet1>
            <rptOwnerStreet2>2361 ROSECRANS AVENUE</rptOwnerStreet2>
            <rptOwnerCity>EL SEGUNDO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90254</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>2010-11-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>260000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.25</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>164481</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 20,000, 200,000, 30,000 and 10,000 shares tendered in Peerless Systems Corporation's tender offer, respectively, by Mr. Bathgate, his wife, the Bathgate Family Partnership, Ltd., and Mr. Bathgate's adult children residing with him.</footnote>
        <footnote id="F2">Includes 27,241, 100,000, 10,000 and 10,000 shares held by Mr. Bathgate, his wife, the Bathgate Family Partnership, Ltd., and Mr. Bathgate's adult children residing with him. Also includes 17,240 shares of restricted common stock held by Mr. Bathgate.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Steven Bathgate</signatureName>
        <signatureDate>2010-11-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
