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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-12-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000315189</issuerCik>
        <issuerName>DEERE &amp; CO</issuerName>
        <issuerTradingSymbol>DE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001196902</rptOwnerCik>
            <rptOwnerName>MARKLEY H J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>DEERE &amp; COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>ONE JOHN DEERE PLACE</rptOwnerStreet2>
            <rptOwnerCity>MOLINE</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>61265</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>$1 Par Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2008-12-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11206</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>37.85</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>147403</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Exempt withholding of shares to satisfy tax withholding obligations upon conversion of restricted stock units to unrestricted shares.</footnote>
        <footnote id="F2">Includes 96,293 restricted stock units granted under the John Deere Omnibus Equity and Incentive Plan to be settled solely in shares.  The reporting person also indirectly owns 10,260 shares beneficially owned by his spouse.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Paul Wilczynski, Assistant Secretary, Deere &amp; Company, Under Power of Attorney</signatureName>
        <signatureDate>2008-12-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
