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

    <schemaVersion>X0508</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2023-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000740806</issuerCik>
        <issuerName>F&amp;M BANK CORP</issuerName>
        <issuerTradingSymbol>fmbm</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001800327</rptOwnerCik>
            <rptOwnerName>Keeler Anne B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O F&amp;M BANK</rptOwnerStreet1>
            <rptOwnerStreet2>205 SOUTH MAIN STREET</rptOwnerStreet2>
            <rptOwnerCity>TIMBERVILLE</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>22853</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-05-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>L</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.82</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1314.77</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes 2.45 shares acquired on May 31, 2022, 2.97 shares acquired on August 29, 2022, 3.01 shares acquired on November 29, 2022, 3.26 shares acquired on March 1, 2023, 3.73 shares acquired on May 30, 2023, 3.54 shares acquired on August 29, 2023, and 4.80 shares acquired on November 29, 2023 under the F&amp;M Bank Corp. Dividend Reinvestment and Stock Purchase Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Krista Suter, Attorney-in-Fact</signatureName>
        <signatureDate>2024-02-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
