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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-05-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000739421</issuerCik>
        <issuerName>CITIZENS FINANCIAL SERVICES INC</issuerName>
        <issuerTradingSymbol>CZFS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001640432</rptOwnerCik>
            <rptOwnerName>LANDIS CHRISTOPHER S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2738 MINNEQUA MAIN ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CANTON</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>17724</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SENIOR VICE PRESIDENT</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON CLASS</value>
            </securityTitle>
            <transactionDate>
                <value>2017-05-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>129</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1900</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <remarks>STOCK AWARDS GRANTED PURSUANT TO THE CITIZENS FINANCIAL SERVICES, INC. 2016 EQUITY INCENTIVE PLAN VEST IN THREE EQUAL ANNUAL INSTALLMENTS COMMENCING ON MAY 11, 2018.</remarks>

    <ownerSignature>
        <signatureName>GINA MARIE BOOR FOR CHRISTOPHER S. LANDIS UNDER POWER OF ATTORNEY DATED 04/21/2015</signatureName>
        <signatureDate>2017-05-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2017-05-11
0
0000739421
CITIZENS FINANCIAL SERVICES INC
CZFS
0001640432
LANDIS CHRISTOPHER S
2738 MINNEQUA MAIN ROAD
CANTON
PA
17724
0
1
0
0
SENIOR VICE PRESIDENT
COMMON CLASS
2017-05-11
4
A
0
129
0
A
1900
D
STOCK AWARDS GRANTED PURSUANT TO THE CITIZENS FINANCIAL SERVICES, INC. 2016 EQUITY INCENTIVE PLAN VEST IN THREE EQUAL ANNUAL INSTALLMENTS COMMENCING ON MAY 11, 2018.
GINA MARIE BOOR FOR CHRISTOPHER S. LANDIS UNDER POWER OF ATTORNEY DATED 04/21/2015
2017-05-12