-----BEGIN PRIVACY-ENHANCED MESSAGE-----
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,
 FZDzJJSa29ztfT/j9HE79/uZxR4+H8yhABsNJt7nTckimgZ1HVv6S6hRgH5d69cR
 vAYSEX8nM/KqYdyA4VFlAA==

<SEC-DOCUMENT>0001198272-06-000013.txt : 20060328
<SEC-HEADER>0001198272-06-000013.hdr.sgml : 20060328
<ACCEPTANCE-DATETIME>20060328101354
ACCESSION NUMBER:		0001198272-06-000013
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060327
FILED AS OF DATE:		20060328
DATE AS OF CHANGE:		20060328

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PUTNAM INVESTMENT GRADE MUNICIPAL TRUST
		CENTRAL INDEX KEY:			0000855048
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				046629611
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE POST OFFICE SQUARE
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
		BUSINESS PHONE:		6172921000

	MAIL ADDRESS:	
		STREET 1:		ONE POST OFFICE SQU
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PUTNAM GEORGE III
		CENTRAL INDEX KEY:			0001200510

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-05901
		FILM NUMBER:		06713675

	MAIL ADDRESS:	
		STREET 1:		PUTNAM LLC
		STREET 2:		ONE POST OFFICE SQUARE L5
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-03-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000855048</issuerCik>
        <issuerName>PUTNAM INVESTMENT GRADE MUNICIPAL TRUST</issuerName>
        <issuerTradingSymbol>pgm</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001200510</rptOwnerCik>
            <rptOwnerName>PUTNAM GEORGE III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PUTNAM LLC</rptOwnerStreet1>
            <rptOwnerStreet2>ONE POST OFFICE SQUARE L5</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Closed-End Fund</value>
            </securityTitle>
            <transactionDate>
                <value>2006-03-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.64</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>George Putnam III</signatureName>
        <signatureDate>2006-03-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----