Donald R. Frederick Sr., 56, who had served since 1946 with both the National American Red Cross and the D.C. Chapter, died Sunday at his home in Kensington of a self-inflicted gunshot wound.

Since 1974, he had been assistant insurance officer at Red Cross national headquarters here. Prior to that, he had served for 18 years as assistant manager of the D.C. Chapter. He originally had joined the Red Cross national headquarters in 1946.

Born in Altoona, Pa, Mr. Frederick came to the Washington area as a youth.

He served as a captain with the U.S. Army from 1942 to 1946, seeing combat duty in the European theater, where he was severely wounded.

While working for the Red Cross after the war, he also attended Benjamin Franklin University, where he graduated in 1949.

Mr. Frederick was a member of the American Legion.

He is survived by his wife, Nora G. Frederick, of the home; to sons, Donald R. Jr., of Santa Fe, N.M., and Robert G., of Washington; his parents, Mr. and Mrs. Benjamin L. Frederick, of Austin, Tex., and three sisters, Gerrie Payne, of Kensington, Betty Rogers of Austin, and Shirely Elgin, of Atlanta, Ga.