Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D dated October 9, 2008 (including amendments thereto) with respect to the securities of Investment Grade Municipal Income Fund Inc. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: March 29, 2010	WESTERN INVESTMENT LLC

	By:	/s/ Arthur D. Lipson
		Name:	Arthur D. Lipson
		Title:	Managing Member

WESTERN INVESTMENT HEDGED PARTNERS L.P.

By:	Western Investment LLC
	General Partner

By:	/s/ Arthur D. Lipson
	Name:	Arthur D. Lipson
	Title:	Managing Member

WESTERN INVESTMENT ACTIVISM PARTNERS LLC

By:	Western Investment LLC
	Managing Member

By:	/s/ Arthur D. Lipson
	Name:	Arthur D. Lipson
	Title:	Managing Member

WESTERN INVESTMENT TOTAL RETURN PARTNERS L.P.

By:	Western Investment LLC
	General Partner

By:	/s/ Arthur D. Lipson
	Name:	Arthur D. Lipson
	Title:	Managing Member

CUSIP NO. 461368102

WESTERN INVESTMENT TOTAL RETURN FUND LTD.

By:	Western Investment LLC
	Investment Manager

By:	/s/ Arthur D. Lipson
	Name:	Arthur D. Lipson
	Title:	Managing Member

	/s/ Arthur D. Lipson
	ARTHUR D. LIPSON

CUSIP NO. 461368102

BENCHMARK PLUS INSTITUTIONAL PARTNERS, L.L.C.

By:	Benchmark Plus Management, L.L.C.
	Managing Member

By:	/s/ Robert Ferguson
	Name:	Robert Ferguson
	Title:	Managing Member

By:	/s/ Scott Franzblau
	Name:	Scott Franzblau
	Title:	Managing Member

BENCHMARK PLUS PARTNERS, L.L.C.

By:	Benchmark Plus Management, L.L.C.
	Managing Member

By:	/s/ Robert Ferguson
	Name:	Robert Ferguson
	Title:	Managing Member

By:	/s/ Scott Franzblau
	Name:	Scott Franzblau
	Title:	Managing Member

BENCHMARK PLUS MANAGEMENT, L.L.C.

By:	/s/ Robert Ferguson
	Name:	Robert Ferguson
	Title:	Managing Member

By:	/s/ Scott Franzblau
	Name:	Scott Franzblau
	Title:	Managing Member

	/s/ Robert Ferguson
	ROBERT FERGUSON

	/s/ Scott Franzblau
	SCOTT FRANZBLAU

INVESTMENT GRADE MUNICIPAL INCOME FUND SC 13D