<?xml version="1.0"?>

<ownershipDocument>

    <documentType>3</documentType>

    <periodOfReport>2003-05-28</periodOfReport>


    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001168054</issuerCik>
        <issuerName>CIMAREX ENERGY CO</issuerName>
        <issuerTradingSymbol>XEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001237480</rptOwnerCik>
            <rptOwnerName>SHONSEY JAMES H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CAO and Controller</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>


    <ownerSignature>
        <signatureName>Paul Korus, attorney-in-fact for James H. Shonsey</signatureName>
        <signatureDate>2003-06-02</signatureDate>
    </ownerSignature>

</ownershipDocument>

