-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Hzs2Au2ogFKkbcGzv5xwl41eABVqfcwljB5J263Ui3u7xdiTs7k8CZzgURSs+iNe
 tWToud5UI50D8bfbhYwlNQ==

<SEC-DOCUMENT>0000754673-10-000033.txt : 20100331
<SEC-HEADER>0000754673-10-000033.hdr.sgml : 20100331
<ACCEPTANCE-DATETIME>20100331102232
ACCESSION NUMBER:		0000754673-10-000033
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100329
FILED AS OF DATE:		20100331
DATE AS OF CHANGE:		20100331

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DANOWSKI JAMES E
		CENTRAL INDEX KEY:			0001235027

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-13580
		FILM NUMBER:		10716885

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SUFFOLK BANCORP
		CENTRAL INDEX KEY:			0000754673
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				112708279
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6 W SECOND ST
		CITY:			RIVERHEAD
		STATE:			NY
		ZIP:			11901
		BUSINESS PHONE:		5167275667

	MAIL ADDRESS:	
		STREET 1:		6 WEST SECOND STREET
		CITY:			RIVERHEAD
		STATE:			NY
		ZIP:			11901
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-03-29</periodOfReport>

    <issuer>
        <issuerCik>0000754673</issuerCik>
        <issuerName>SUFFOLK BANCORP</issuerName>
        <issuerTradingSymbol>SUBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001235027</rptOwnerCik>
            <rptOwnerName>DANOWSKI JAMES E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUFFOLK BANCORP</rptOwnerStreet1>
            <rptOwnerStreet2>4 WEST SECOND STREET, PO BOX 9000</rptOwnerStreet2>
            <rptOwnerCity>RIVERHEAD</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11901</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Suffolk Bancorp Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-03-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>124.884</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>31.3623</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17691.069</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Douglas Ian Shaw Power of Attorney for James E. Danowski</signatureName>
        <signatureDate>2010-03-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----