Dr. Fred R. Sanderson, 85, a former chief surgeon at Georgetown University Hospital who was president of the D.C. Medical Society in the mid-1940s, died Sunday at the Bethesda Retirement and Nursing Center in Chevy Chase after a heart attack.

Dr. Sanderson was a general surgeon who specialized in abdominal surgery. He practiced in Washington for 50 years before retiring in 1973.

He joined the faculty of Georgetown University's medical school in 1923. In 1942, he was named director of the school's surgery department and chief surgeon of the Georgetown University Hospital, posts he held for about 10 years.

Dr. Sanderson was born in Washington. He was a graduate of Eastern High School and earned his doctorate of medicine at Georgetown University.

He was a fellow and worked as a surgery assistant at the Mayo Clinic in Rochester, Minn., before returning to Washington in 1922.

He was a founder and past president of the Eastern Surgical Society. His other professional memberships included the American College of Surgeons, the Southern Surgical Society, and the American Board of Surgery.

Dr. Sanderson was Master of Fox Hounds of the Potomac Hunt for 10 years before stepping down in 1943. He also had belonged to the Chevy Chase Country Club and had been president of the Friendly Sons of St. Patrick.

He had been a member of the Catholic Church of the Little Flower in Bethesda.

His wife, the former Margaret Madden, died in 1974.

Dr. Sanderson had resided in Kenwood for 40 years.

He is survived by three daughters, Margaret Amussen, of Eureka Springs, Ark., M. Louise McChesney, of Kensington, and Mary Ann Mougey, of Hudson, Ohio; a brother, John M., of Hagerstown, Md.; 17 grandchildren, and four great-grand-children.

The family suggests that expressions of sympathy be in the form of contributions to the Merrick Boys Camp, 1721 Rhode Island Ave. NW.