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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-12-11</periodOfReport>

    <issuer>
        <issuerCik>0000009326</issuerCik>
        <issuerName>BALCHEM CORP</issuerName>
        <issuerTradingSymbol>BCPC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001236561</rptOwnerCik>
            <rptOwnerName>TELEVANTOS JOHN Y</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BALCHEM CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>52 SUNRISE PARK ROAD</rptOwnerStreet2>
            <rptOwnerCity>NEW HAMPTON</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10958</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-12-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>882</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>81.81</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30147</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On December 11, 2013, the Company granted 1,957 restricted shares under the Company's Long-Term Incentive Program. The stock was subject to a repurchase option in favor of the Issuer and to restrictions on transfer until it vested in accordance with the provisions of the Restricted Stock Purchase Agreement on December 11, 2013. 882 of the 1,957 shares that vested December 11, 2017 were withheld to cover taxes.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John Y. Televantos by, Attorney in Fact, Mark A. Stach</signatureName>
        <signatureDate>2017-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
