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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 F+fPy1bzORCeY58I1QN2NX0QJo1VQxHCjRFg3pFkNDSwbNN9m3o3qhCAOGOR40hl
 5KzErin+m0XN9x9YMdS23A==

<SEC-DOCUMENT>0001055745-03-000010.txt : 20030807
<SEC-HEADER>0001055745-03-000010.hdr.sgml : 20030807
<ACCEPTANCE-DATETIME>20030807164906
ACCESSION NUMBER:		0001055745-03-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030807
FILED AS OF DATE:		20030807

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARTIN LARRY W
		CENTRAL INDEX KEY:			0001055745

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-06379
		FILM NUMBER:		03829199

	BUSINESS ADDRESS:	
		STREET 1:		C/O NUVEEN INVESTMENTS
		STREET 2:		333 W. WACKER DRIVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3129177700

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NUVEEN INSURED MUNICIPAL OPPORTUNITY FUND INC
		CENTRAL INDEX KEY:			0000878242
		IRS NUMBER:				363777460
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		333 WEST WACKER DR
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3129178200

	MAIL ADDRESS:	
		STREET 1:		333 W WACKER
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>mar6.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
	<periodOfReport>2003-08-07</periodOfReport>
	<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000878242</issuerCik>
        <issuerName>NUVEEN INSURED MUNICIPAL OPPORTUNITY FUND INC</issuerName>
        <issuerTradingSymbol>NIO</issuerTradingSymbol>
	</issuer>
	<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001055745</rptOwnerCik>
            <rptOwnerName>MARTIN LARRY W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
			<isDirector>0</isDirector>
			<isOfficer>1</isOfficer>
			<isTenPercentOwner>0</isTenPercentOwner>
			<isOther>0</isOther>
			<officerTitle>VP and Ast. Secretary</officerTitle>
		</reportingOwnerRelationship>
	</reportingOwner>
	<nonDerivativeTable>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2003-08-07</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>P</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>15.11</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>A</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>1000</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
	</nonDerivativeTable>
	<footnotes>
	</footnotes>
	<remarks>
	</remarks>
	<ownerSignature>
		<signatureName>/s/ Martin, Larry W.</signatureName>
		<signatureDate>2003-08-07</signatureDate>
	</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----