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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-09-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000701288</issuerCik>
        <issuerName>ATRION CORP</issuerName>
        <issuerTradingSymbol>ATRI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001920839</rptOwnerCik>
            <rptOwnerName>Bankes Jeannette</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE ALLENTOWN PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>ONE ALLENTOWN PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>ALLEN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75002</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>2023-09-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>186</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>444.03</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>186</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The Issuer's director compensation policy provides for a grant to the Reporting Person of an annual award of common stock in an amount equal to $124,000.  On September 20, 2023, the Compensation Committee granted an award to Ms. Jeannette Bankes in an amount equal to $82,666.67 which is the pro rated portion of the annual amount for the remaining portion of the year until the Annual Stockholders meeting.</footnote>
        <footnote id="F2">The number of shares of common stock issued for the award described above was based on the closing price per share of the Issuer's common stock on September 20, 2023, or $444.03.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Cindy Ferguson, Attorney-in-fact</signatureName>
        <signatureDate>2023-09-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
