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

    <documentType>3</documentType>
<periodOfReport>2003-12-12</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000887591</issuerCik>
        <issuerName>FIBERMARK INC</issuerName>
        <issuerTradingSymbol>FMK</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001272927</rptOwnerCik>
            <rptOwnerName>HANLEY JOHN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState>X1</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>VP and CFO</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<derivativeTable>
<derivativeHolding>
<securityTitle>
<value>Option to Buy (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice>
<value>4.34</value>
</conversionOrExercisePrice>
<exerciseDate>
<footnoteId id="F1"/>
</exerciseDate>
<expirationDate>
<value>2008-07-21</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Class A Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>5000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeHolding>
</derivativeTable>
<footnotes>
<footnote id="F1">Options granted on July 21, 2003, under the 1997 Stock Option Plan for Employees and Officers of FiberMark, Inc., will vest at a rate of 20% per year over a period of five (5) years, commencing on the first anniversary of the grant date and continuing thereafter annually.</footnote>
</footnotes>
<remarks></remarks>
<ownerSignature>
<signatureName>John E. Hanley</signatureName>
<signatureDate>2003-12-15</signatureDate>
</ownerSignature>
</ownershipDocument>

