<?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>0001215809</rptOwnerCik>
            <rptOwnerName>BLACK RANDALL E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>POST OFFICE BOX 19</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LIBERTY</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>16930</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO &amp; 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>1001</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25775.1538</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>COMMON CLASS</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>281</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY SPOUSE</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </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 RANDALL E. BLACK UNDER POWER OF ATTORNEY DATED 08/30/2002</signatureName>
        <signatureDate>2017-05-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2017-05-11
0
0000739421
CITIZENS FINANCIAL SERVICES INC
CZFS
0001215809
BLACK RANDALL E
POST OFFICE BOX 19
LIBERTY
PA
16930
1
1
0
0
CEO & PRESIDENT
COMMON CLASS
2017-05-11
4
A
0
1001
0
A
25775.1538
D
COMMON CLASS
281
I
BY SPOUSE
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 RANDALL E. BLACK UNDER POWER OF ATTORNEY DATED 08/30/2002
2017-05-12