-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 B33142sguh5hXVdE/mYSwTnVS+lNuRfbCli8cCzvDY2wK+DzXOMH/pazoq7b+trI
 EGGfSk3Lr5/SkTnLrHJVOQ==

<SEC-DOCUMENT>0001127602-10-030597.txt : 20101214
<SEC-HEADER>0001127602-10-030597.hdr.sgml : 20101214
<ACCEPTANCE-DATETIME>20101214165427
ACCESSION NUMBER:		0001127602-10-030597
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101210
FILED AS OF DATE:		20101214
DATE AS OF CHANGE:		20101214

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Santee David S
		CENTRAL INDEX KEY:			0001383436

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12252
		FILM NUMBER:		101251115

	MAIL ADDRESS:	
		STREET 1:		C/O EQUITY RESIDENTIAL
		STREET 2:		TWO NORTH RIVERSIDE PLAZA, SUITE 400
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EQUITY RESIDENTIAL
		CENTRAL INDEX KEY:			0000906107
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				363877868
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		EQUITY RESIDENTIAL
		STREET 2:		TWO NORTH RIVERSIDE PLAZA, SUITE 400
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3129281178

	MAIL ADDRESS:	
		STREET 1:		TWO NORTH RIVERSIDE PLAZA
		STREET 2:		SUITE 400
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	EQUITY RESIDENTIAL PROPERTIES TRUST
		DATE OF NAME CHANGE:	19930524
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-10</periodOfReport>

    <issuer>
        <issuerCik>0000906107</issuerCik>
        <issuerName>EQUITY RESIDENTIAL</issuerName>
        <issuerTradingSymbol>EQR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001383436</rptOwnerCik>
            <rptOwnerName>Santee David S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO NORTH RIVERSIDE PLAZA, SUITE 400</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares Of Beneficial Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16571</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>38.57</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24456</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares Of Beneficial Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16571</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>51.7885</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7885</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares Of Beneficial Interest</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1835.4679</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(k) Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares Of Beneficial Interest</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26702.399</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>SERP Account</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-qualified Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>38.57</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-12-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16571</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-02-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares Of Beneficial Interest</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16571</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8286</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Direct total includes restricted shares of the Company scheduled to vest in the future.</footnote>
        <footnote id="F2">The price represents the weighted average price of the shares sold.  The shares were sold within a range of $51.78 to $51.81.  The reporting person will provide, upon request by the SEC staff, the issuer, or any security holder of the issuer, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F3">Represents shares acquired through profit sharing contributions and dividend reinvestment activity in the reporting person's account with the Equity Residential Advantage 401(k) Retirement Savings Plan, a plan qualified under Section 401(k) of the Internal Revenue Code of 1986, as amended.  Such shares represent acquisitions through October 8, 2010.</footnote>
        <footnote id="F4">Represents shares owned by Principal Trust Company, as Trustee of the Equity Residential Supplemental Executive Retirement Plan, for the benefit of the reporting person.</footnote>
        <footnote id="F5">Represents share options scheduled to vest in approximately three equal installments on February 7, 2009, February 7, 2010 and February 7, 2011.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>s/ By: Yasmina Duwe, Attorney-in-fact</signatureName>
        <signatureDate>2010-12-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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