<?xml version="1.0"?><ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType><periodOfReport>2003-10-21</periodOfReport>
    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001158324</issuerCik>
        <issuerName>COGENT COMMUNICATIONS GROUP INC</issuerName>
        <issuerTradingSymbol>COI</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001256821</rptOwnerCik>
            <rptOwnerName>CARUS MICHAEL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>41 MADISON AVE</rptOwnerStreet1>
            <rptOwnerStreet2>25TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10010</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><ownerSignature><signatureName>Michael Carus</signatureName><signatureDate>2003-10-30</signatureDate></ownerSignature></ownershipDocument>



