James Clarence Fritz, 75, a retired supervisory research chemist with the Food and Drug Administration, died Nov. 12 at a convalescent center in Lawrence, Kan., of complications after heart surgery. He lived in Bowie.

Mr. Fritz was born in Berlin, Pa., and graduated from Pennsylvania State University. He moved to the Washington area in 1930 and went to work at the Agriculture Department as a biologist.

He moved to Elgin, Ill., in 1937 and became director of Bordens Experimental Laboratories. From 1952 to 1965, he was the director of nutritional research at Dawes Laboratories in Arlington Heights, Ill. He returned to Washington in 1965 and joined the FDA, where he specialized in nutrition. He retired in 1978.

Mr. Fritz received FDA's Award of Merit in 1977.

He was coauthor of the book "Scientific Feeding of Chickens."

He was a member of the American Association for the Advancement of Science, the Poultry Science Association, and the Association of Vitamin Chemists, of which he was a past president.

A marksman in private life, he was the first recipient of the Fritz Trophy, an award named for him by the Maryland/D.C. Rifleman Association and presented annually for the promotion of marksmanship and firearms safety.

His wife, the former Jeannette Moore Blair, died in 1979. Survivors include a son, Richard B., of Boulder, Colo.; a daughter, Margaret M.F. Baker of Baldwin City, Kan.; a brother, H. Henry Fritz of Berlin, and four grandchildren.