Retired Air Force Col. William F. Dufault, 61, a special assistant for the National Health Agencies in Alexandria and a veteran of World War II and the Korean and Vietnam wars, died of cancer Wednesday at Malcolm Grow Hospital at Andrews Air Force Base. He lived in Annandale.

Col. Dufault was born in Topsham, Maine. He entered the Army while attending Boston College and was stationed in France and in the Caribbean during World War II.

He separated from the Army after the war and entered the Air Force in 1948. He served in Saigon, Vietnam, during the Korean war and in Cambodia during the Vietnam war. His other duty included tours at the Pentagon and in West Germany, France and Belgium.

Col. Dufault was assigned to Special Air Missions at Andrews Air Force Base when he retired from active duty in 1973.

After his military retirement, he joined the National Health Agencies.

Survivors include his wife, the former Alice Burke, two daughters, Anne Lourdes and Mary Camille, and two sons, Bill Jr. and Vertume Thomas, all of Annandale; four sisters, Beatrice Hyde of Bath, Maine., Blanche Butler of Wakefield, Mass., Louise Dufault of Albuquerque and Mother Alma, a nun, of Rome, Italy, and five brothers, Leo, of Wakefield, Joe, of Dunstable, Mass., Vertume, of Lowell, Mass., Norman, of Fort Lauderdale, Fla., and the Rev. Omer Dufault of Stowe, Vt.

The family suggests that expressions of sympathy be in the form of contributions to the Franciscan Missionary of Mary, Provencial House, 225 East 45th Street, New York, N.Y. 10017.