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<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-09-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000029534</issuerCik>
        <issuerName>DOLLAR GENERAL CORP</issuerName>
        <issuerTradingSymbol>DG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001472698</rptOwnerCik>
            <rptOwnerName>KKR Fund Holdings L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KOHLBERG KRAVIS ROBERTS &amp; CO. L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>9 WEST 57TH STREET, SUITE 4200</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001432741</rptOwnerCik>
            <rptOwnerName>KKR 2006 Fund L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KOHLBERG KRAVIS ROBERTS &amp; CO. L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>9 WEST 57TH STREET, SUITE 4200</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001432739</rptOwnerCik>
            <rptOwnerName>KKR Associates 2006 LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KOHLBERG KRAVIS ROBERTS &amp; CO. L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>9 WEST 57TH STREET, SUITE 4200</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001432740</rptOwnerCik>
            <rptOwnerName>KKR 2006 GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KOHLBERG KRAVIS ROBERTS &amp; CO. L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>9 WEST 57TH STREET, SUITE 4200</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.875 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2011-09-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10281443</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.7075</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>78692005</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held through Buck Holdings, L.P. and KKR 2006 Fund L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.875 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2011-09-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2169694</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.7075</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16606381</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held through Buck Holdings, L.P. and KKR PEI Investments, L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.875 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2011-09-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>356894</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.7075</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2731590</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held through Buck Holdings, L.P. and 8 North America Investor L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.875 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2011-09-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1526566</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.7075</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11684016</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held through Buck Holdings, L.P. and Buck Holdings Co-Invest, L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.875 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2011-09-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>238763</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.7075</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1827437</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held through Buck Holdings, L.P. and KKR Partners III, L.P.</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                    <footnoteId id="F10"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This amount represents the $34.75 secondary public offering price per share of common stock, par value $0.875 per share (&quot;Common Stock&quot;), of Dollar General Corporation less the underwriting discount of $1.0425 per share of Common Stock.</footnote>
        <footnote id="F2">Buck Holdings, L.P. directly holds all of the shares of Common Stock reported herein.  Buck Holdings, LLC is the general partner of Buck Holdings, L.P.  The membership interests of Buck Holdings, LLC are held by a private investor group, including affiliates of Kohlberg Kravis Roberts &amp; Co. L.P., Goldman, Sachs &amp; Co. and other equity investors.</footnote>
        <footnote id="F3">KKR 2006 Fund L.P. may be deemed to indirectly beneficially own these shares of Common Stock by virtue of the membership interests it holds in Buck Holdings, LLC.  The sole general partner of the KKR 2006 Fund L.P. is KKR Associates 2006 L.P., and the sole general partner of KKR Associates 2006 L.P. is KKR 2006 GP LLC.  The designated member of KKR 2006 GP LLC is KKR Fund Holdings L.P.</footnote>
        <footnote id="F4">KKR PEI Investments, L.P. may be deemed to indirectly beneficially own these shares of Common Stock by virtue of the membership interests it holds in Buck Holdings, LLC.  The sole general partner of KKR PEI Investments, L.P. is KKR PEI Associates, L.P., and the sole general partner of KKR PEI Associates, L.P. is KKR PEI GP Limited.  The sole shareholder of KKR PEI GP Limited is KKR Fund Holdings L.P.</footnote>
        <footnote id="F5">8 North America Investor L.P. may be deemed to indirectly beneficially own these shares of Common Stock by virtue of the membership interests it holds in Buck Holdings, LLC.  The sole general partner of 8 North America Investor L.P. is KKR Associates 8 NA L.P., and the sole general partner of KKR Associates 8 NA L.P. is KKR 8 NA Limited.  The sole shareholder of KKR 8 NA Limited is KKR Fund Holdings L.P.</footnote>
        <footnote id="F6">Buck Holdings Co-Invest, LP may be deemed to indirectly beneficially own these shares of Common Stock by virtue of the membership interests it holds in Buck Holdings, LLC.  Buck Holdings Co-Invest GP, LLC is the sole general partner of Buck Holdings Co-Invest, LP, and the managing member of Buck Holdings Co-Invest GP, LLC is KKR Associates 2006 L.P. The sole general partner of KKR Associates 2006 L.P. is KKR 2006 GP LLC.  The designated member of KKR 2006 GP LLC is KKR Fund Holdings L.P.</footnote>
        <footnote id="F7">The general partners of KKR Fund Holdings L.P. are KKR Fund Holdings GP Limited and KKR Group Holdings L.P.  The sole shareholder of KKR Fund Holdings GP Limited is KKR Group Holdings L.P.  The sole general partner of KKR Group Holdings L.P. is KKR Group Limited.  The sole shareholder of KKR Group Limited is KKR &amp; Co. L.P.  The sole general partner of KKR &amp; Co. L.P. is KKR Management LLC.  The designated members of KKR Management LLC are Henry R. Kravis and George R. Roberts.</footnote>
        <footnote id="F8">KKR Partners III, L.P. may be deemed to indirectly beneficially own these shares of Common Stock by virtue of the membership interests it holds in Buck Holdings, LLC.  The sole general partner of KKR Partners III, L.P.is KKR III GP LLC.  The managers of KKR III GP LLC are Messrs. Kravis and Roberts.</footnote>
        <footnote id="F9">Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein, except to the extent of such Reporting Person's pecuniary interest therein.  The filing of this statement shall not be deemed to be an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the Reporting Persons are the beneficial owners of any securities reported herein.</footnote>
        <footnote id="F10">Because no more than 10 reporting persons can file any one Form 4 through the Securities and Exchange Commission's EDGAR system, KKR Fund Holdings GP Limited, KKR Group Holdings L.P., KKR Group Limited, KKR &amp; Co. L.P., KKR Management LLC and Messrs. Kravis and Roberts have filed a separate Form 4.</footnote>
    </footnotes>

    <remarks>(11) Mr. Kreider is signing in his capacity as attorney-in-fact for William J. Janetschek, a director of KKR Fund Holdings GP Limited, the general partner of KKR Fund Holdings L.P., the designated member of KKR 2006 GP LLC, the sole general partner of KKR Associates 2006 L.P., the sole general partner of KKR 2006 Fund L.P.  (12) Mr. Kreider is signing in his capacity as attorney-in-fact for Mr. Janetschek, a director of KKR Fund Holdings GP Limited, the general partner of KKR Fund Holdings L.P., the designated member of KKR 2006 GP LLC, the sole general partner of KKR Associates 2006 L.P.  (13) Mr. Kreider is signing in his capacity as attorney-in-fact for Mr. Janetschek, a director of KKR Fund Holdings GP Limited, the general partner of KKR Fund Holdings L.P., the designated member of KKR 2006 GP LLC.  (14) Mr. Kreider is signing in his capacity as attorney-in-fact for Mr. Janetschek, a director of KKR Fund Holdings GP Limited, the general partner of KKR Fund Holdings L.P.</remarks>

    <ownerSignature>
        <signatureName>/s/ Richard J. Kreider, KKR 2006 Fund L.P. (11)</signatureName>
        <signatureDate>2011-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard J. Kreider, KKR Associates 2006 L.P. (12)</signatureName>
        <signatureDate>2011-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard J. Kreider, KKR 2006 GP LLC (13)</signatureName>
        <signatureDate>2011-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Richard J. Kreider, KKR Fund Holdings L.P. (14)</signatureName>
        <signatureDate>2011-09-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
