Kendall M. Barnes, 71, who retired in 1975 as general counsel of the Army Materiel Command and earlier had been one of the chief judicial lawyers for the Justice Department, died of cancer Friday at Mount Vernon Hospital.

He went to work with the command in 1962 and had received a commendation for outstanding performance.

Mr. Barnes served as assistant chief of the Court of Claims Section of the Justice Department from 1944 to 1962. Major cases with which he was associated included the Dixon-Yates power plant controversy. He received the attorney general's outstanding service award in 1957, and in 1961 was presented the Justice Tom C. Clark Award given by the Federal Bar Association to the outstanding career lawyer in federal service.

He was born in Coldwater, Mich., and graduated from Princeton University and the University of Pennsylvania Law School. He practiced law in New York City from 1934 until 1941, when he came here to serve in the office of the general counsel of the War Production Board. He lived in Alexandria.

His wife of 38 years, Pauline A. Barnes, died in August.

He is survived by a son, Kendall M. Jr., of Salem, Ore.; two daughters, Gayle Blomme of Grand Rapids, Mich., and Nancy Barnes of Alexandria; a stepson, Reginald Fentner of Glenmoore, Pa., and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.