    <SEC-DOCUMENT>0001133228-24-007100-index.html : 20240730
    <SEC-HEADER>0001133228-24-007100.hdr.sgml : 20240730
    <ACCEPTANCE-DATETIME>20240730112521
    ACCESSION NUMBER:		0001133228-24-007100
    CONFORMED SUBMISSION TYPE:	N-CSRS
    PUBLIC DOCUMENT COUNT:		9
    CONFORMED PERIOD OF REPORT:	20240531
    FILED AS OF DATE:		20240730
    DATE AS OF CHANGE:		20240730
    EFFECTIVENESS DATE:		20240730

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			Western Asset Investment Grade Defined Opportunity Trust Inc.
    		CENTRAL INDEX KEY:			0001462586
    		ORGANIZATION NAME:
    		IRS NUMBER:				000000000
    		STATE OF INCORPORATION:			MD
    		FISCAL YEAR END:			1130

    	FILING VALUES:
    		FORM TYPE:		N-CSRS
    		SEC ACT:		1940 Act
    		SEC FILE NUMBER:	811-22294
    		FILM NUMBER:		241155549

    	BUSINESS ADDRESS:
    		STREET 1:		620 EIGHTH AVENUE
    		STREET 2:		47TH FLOOR
    		CITY:			NEW YORK
    		STATE:			NY
    		ZIP:			10018
    		BUSINESS PHONE:		888-777-0102

    	MAIL ADDRESS:
    		STREET 1:		620 EIGHTH AVENUE
    		STREET 2:		47TH FLOOR
    		CITY:			NEW YORK
    		STATE:			NY
    		ZIP:			10018
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>N-CSRS
    <SEQUENCE>1
    <FILENAME>waigdoti-efp8220_ncsrs.htm
    <DESCRIPTION>WESTERN ASSET INVESTMENT GRADE DEFINED OPPORTUNITY TRUST INC. (IGI) - N-CSRS
    <TEXT>
    Document 1 - file: waigdoti-efp8220_ncsrs.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.CERT
    <SEQUENCE>2
    <FILENAME>waigdoti-efp8220_ex99cert.htm
    <DESCRIPTION>CERTIFICATIONS PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002
    <TEXT>
    Document 2 - file: waigdoti-efp8220_ex99cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.906CERT
    <SEQUENCE>3
    <FILENAME>waigdoti-efp8220_ex99906cert.htm
    <DESCRIPTION>CERTIFICATIONS PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002
    <TEXT>
    Document 3 - file: waigdoti-efp8220_ex99906cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>img0ba7cedd5.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: img0ba7cedd5.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>img2dd281516.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: img2dd281516.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>img42fc70834.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: img42fc70834.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>img172d1b111.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: img172d1b111.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>img7962417b2.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: img7962417b2.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>imge2c337163.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: imge2c337163.gif

    </DOCUMENT>
    </SEC-DOCUMENT>