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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-11-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000027096</issuerCik>
        <issuerName>DATASCOPE CORP</issuerName>
        <issuerTradingSymbol>DSCP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001235546</rptOwnerCik>
            <rptOwnerName>KANTOR SCOTT D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DATASCOPE CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>14 PHILIPS PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>MONTVALE, NJ</rptOwnerCity>
            <rptOwnerState>X1</rptOwnerState>
            <rptOwnerZipCode>07645</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP; Finance &amp; Admin &amp; CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>35.875</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-11-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-11-28</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-11-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Option vests in 4 equal installments on each of the first 4 anniversaries of the Grant date (11/28/05). (a)However, prior to the fifth anniversary of the grant date, the vested portion of the option is exercisable only if the average of the high and low sale prices of the Issuer's Common Stock as quoted on The NASDAQ Stock Market on the trading day immmediately preceding the exercise date is equal to or greater than $41.00. After the fifth anniversary of the grant date, the option is fully exercisable, without any regard to the Issuer's Common Stock.</footnote>
        <footnote id="F2">See Column 2 for exercise price.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Scott D. Kantor</signatureName>
        <signatureDate>2005-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
