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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 LKZ/3P1M9OnLZkpKcgT+dWrnJkaDFkkfMTGbLjzKV3o33pzgH24Q6lpHtFga/7Rl
 FrDFxpQulGXN9bwcOlA76Q==

<SEC-DOCUMENT>0001140361-11-002932.txt : 20110114
<SEC-HEADER>0001140361-11-002932.hdr.sgml : 20110114
<ACCEPTANCE-DATETIME>20110114154253
ACCESSION NUMBER:		0001140361-11-002932
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110101
FILED AS OF DATE:		20110114
DATE AS OF CHANGE:		20110114

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sapack Kenneth
		CENTRAL INDEX KEY:			0001383990

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-00599
		FILM NUMBER:		11530252

	MAIL ADDRESS:	
		STREET 1:		132 GOOD HILL ROAD
		CITY:			WOODBURY
		STATE:			CT
		ZIP:			06798

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EASTERN CO
		CENTRAL INDEX KEY:			0000031107
		STANDARD INDUSTRIAL CLASSIFICATION:	CUTLERY, HANDTOOLS & GENERAL HARDWARE [3420]
		IRS NUMBER:				060330020
		STATE OF INCORPORATION:			CT
		FISCAL YEAR END:			0102

	BUSINESS ADDRESS:	
		STREET 1:		112 BRIDGE ST
		STREET 2:		P O BOX 460
		CITY:			NAUGATUCK
		STATE:			CT
		ZIP:			06770
		BUSINESS PHONE:		2037292255

	MAIL ADDRESS:	
		STREET 1:		112 BRIDGE STREET
		STREET 2:		P O BOX 460
		CITY:			NAUGATUCK
		STATE:			CT
		ZIP:			06770
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 5
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2011-01-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000031107</issuerCik>
        <issuerName>EASTERN CO</issuerName>
        <issuerTradingSymbol>EML</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001383990</rptOwnerCik>
            <rptOwnerName>Sapack Kenneth</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>112 BRIDGE STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NAUGATUCK</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06770</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Kenneth R. Sapack</signatureName>
        <signatureDate>2011-01-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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