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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000070858-10-000159.txt : 20100210
<SEC-HEADER>0000070858-10-000159.hdr.sgml : 20100210
<ACCEPTANCE-DATETIME>20100210164518
ACCESSION NUMBER:		0000070858-10-000159
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100129
FILED AS OF DATE:		20100210
DATE AS OF CHANGE:		20100210

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BLACKROCK INSURED MUNICIPAL INCOME TRUST
		CENTRAL INDEX KEY:			0001181187
		IRS NUMBER:				000000000
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		100 BELLEVUE PARKWAY
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19809
		BUSINESS PHONE:		800-441-7762

	MAIL ADDRESS:	
		STREET 1:		100 BELLEVUE PARKWAY
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19809

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BLACKROCK MUNICIPAL INCOME TRUST III
		DATE OF NAME CHANGE:	20020819

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BANK OF AMERICA CORP /DE/
		CENTRAL INDEX KEY:			0000070858
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21178
		FILM NUMBER:		10588374

	BUSINESS ADDRESS:	
		STREET 1:		BANK OF AMERICA CORPORATE CENTER
		STREET 2:		100 N TRYON ST
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28255
		BUSINESS PHONE:		7043868486

	MAIL ADDRESS:	
		STREET 1:		BANK OF AMERICA CORPORATE CENTER
		STREET 2:		100 N TRYON ST
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28255

	FORMER NAME:	
		FORMER CONFORMED NAME:	BANKAMERICA CORP/DE/
		DATE OF NAME CHANGE:	19981022

	FORMER NAME:	
		FORMER CONFORMED NAME:	NATIONSBANK CORP
		DATE OF NAME CHANGE:	19920703

	FORMER NAME:	
		FORMER CONFORMED NAME:	NCNB CORP
		DATE OF NAME CHANGE:	19920107

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MERRILL LYNCH, PIERCE, FENNER & SMITH INC.
		CENTRAL INDEX KEY:			0000728612
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21178
		FILM NUMBER:		10588373

	BUSINESS ADDRESS:	
		STREET 1:		4 WORLD FINANCIAL CENTER
		STREET 2:		NORTH TOWER
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10080
		BUSINESS PHONE:		2126702273

	MAIL ADDRESS:	
		STREET 1:		4 WORLD FINANCIAL CENTER
		STREET 2:		NORTH TOWER
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10080

	FORMER NAME:	
		FORMER CONFORMED NAME:	MERRILL LYNCH PIERCE FENNER & SMITH INC
		DATE OF NAME CHANGE:	19920929

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Blue Ridge Investments, L.L.C.
		CENTRAL INDEX KEY:			0001453700
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21178
		FILM NUMBER:		10588372

	BUSINESS ADDRESS:	
		STREET 1:		214 NORTH TRYON STREET
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28255
		BUSINESS PHONE:		980-388-5633

	MAIL ADDRESS:	
		STREET 1:		214 NORTH TRYON STREET
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28255
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2010-01-29</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001181187</issuerCik>
        <issuerName>BLACKROCK INSURED MUNICIPAL INCOME TRUST</issuerName>
        <issuerTradingSymbol>BYM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000070858</rptOwnerCik>
            <rptOwnerName>BANK OF AMERICA CORP /DE/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BANK OF AMERICA CORPORATE CENTER</rptOwnerStreet1>
            <rptOwnerStreet2>100 N TRYON ST</rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28255</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000728612</rptOwnerCik>
            <rptOwnerName>MERRILL LYNCH, PIERCE, FENNER &amp; SMITH INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4 WORLD FINANCIAL CENTER</rptOwnerStreet1>
            <rptOwnerStreet2>NORTH TOWER</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10080</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001453700</rptOwnerCik>
            <rptOwnerName>Blue Ridge Investments, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>214 NORTH TRYON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28255</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Auction Rate Preferred</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>208</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Subsidiaries</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The Auction Rate Preferred Shares (&quot;Shares&quot;) reported in Table 1 represent 185 shares beneficially owned by Blue Ridge Investments, L.L.C. (&quot;Blue Ridge&quot;), 22 shares beneficially owned by Bank of America, N.A. (&quot;BANA&quot;) and 1 share beneficially owned by Merrill Lynch, Pierce, Fenner &amp; Smith Incorporated (&quot;MLPFS&quot;). Blue Ridge is a wholly owned subsidiary of BANA. MLPFS and BANA are wholly owned subsidiaries of Bank of America Corporation (&quot;Bank of America&quot;).</footnote>
    </footnotes>

    <remarks>The Shares reported herein represent Bank of America's combined holdings in multiple series of auction rate preferred securities of the issuer, which are treated herein as one class of securities in accordance with the Auction Rate Securities---Exemptive Relief no-action letter issued by the Securities and Exchange Commission  (SEC) on September 22, 2008. Bank of America undertakes to provide upon request by the SEC, the issuer or a security holder of the issuer, complete information regarding the number of equity securities of the issuer purchased or sold at each different price and date of all transactions in such securities that occurred after Bank of America became a 10% owner but prior to the date of this filing.</remarks>

    <ownerSignature>
        <signatureName>Bank of America Corporation and Bank of America, N.A., By:/s/ Angelina L. Richardson, Title: Vice President</signatureName>
        <signatureDate>2010-02-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Merrill Lynch, Pierce, Fenner &amp; Smith Incorporated, By:/s/ Lawrence Emerson, Title: Attorney-In-Fact</signatureName>
        <signatureDate>2010-02-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Blue Ridge Investments, L.L.C. By:/s/ Gary Tsuyuki, Title: Managing Director</signatureName>
        <signatureDate>2010-02-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
