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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 A5R3awKxNkKbwuOwQ2KETHc83Y4kw9eRkqkHaoQw3UStU6ABSBiBcTSLeR83V42k
 wFzav/YDnwhpi0dKu07uhg==

<SEC-DOCUMENT>0001306550-04-000049.txt : 20041126
<SEC-HEADER>0001306550-04-000049.hdr.sgml : 20041125
<ACCEPTANCE-DATETIME>20041126151856
ACCESSION NUMBER:		0001306550-04-000049
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20041116
FILED AS OF DATE:		20041126
DATE AS OF CHANGE:		20041126

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HUBBARD ROBERT GLENN
		CENTRAL INDEX KEY:			0001283051

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21178
		FILM NUMBER:		041169298

	MAIL ADDRESS:	
		STREET 1:		609 URIS HALL
		STREET 2:		3022 BROADWAY
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10027

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BLACKROCK INSURED MUNICIPAL INCOME TRUST
		CENTRAL INDEX KEY:			0001181187
		IRS NUMBER:				816105962
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		100 BELLEVUE PARKWAY
		STREET 2:		MUTUAL FUND DEPARTMENT
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19809
		BUSINESS PHONE:		888-825-2257

	MAIL ADDRESS:	
		STREET 1:		100 BELLEVUE PARKWAY
		STREET 2:		MUTUAL FUND DEPARTMENT
		CITY:			WILMINGTON
		STATE:			DE
		ZIP:			19809

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BLACKROCK MUNICIPAL INCOME TRUST III
		DATE OF NAME CHANGE:	20020819
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2004-11-16</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001283051</rptOwnerCik>
            <rptOwnerName>HUBBARD ROBERT GLENN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>40 EAST 52ND STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>Robert Glenn Hubbard</signatureName>
        <signatureDate>2004-11-24</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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