Walter McFarlan Fallon, 68, a retired post office superintendent and a longtime Washington area resident, died Friday at Anne Arundel General Hospital. He had a heart ailment.

Mr. Fallon began working for the old Post Office Department in 1941 as a letter carrier and later was promoted to superintendent. He was superintendent of the Woodmoor branch post office for about five years before retiring in 1972.

He was born in Connecticut and moved to this area with his family at an early age. He lived in Silver Spring for 50 years and was a graduate of old Takoma-Silver Spring High School. He was a former member of St. John the Evangelist Catholic Church in Silver Spring.

In 1974, Mr. Fallon and his wife of 46 years, Lily, moved to Edgewater, Md. He was active in Our Lady of Perpetual Help Catholic Church there and was treasurer of the church's senior citizens group.

In addition to his wife, Mr. Fallon's survivors include three sons, Frederick W., of Bowie, Michael M., of Edgewater, and Brian P., of Kensington; three daughters, Dulcie D. Davis of Edgewater, Marcia D. Riedmuller of Derwood, Md., and Susan L. Smith of Hyattsville; two sisters, Elizabeth L. Fallon of Virginia and Jean F. Burke of Silver Spring, 22 grandchildren and one great-grandchild.

The family suggests that expressions of sympathy be in the form of contributions to the American Heart Association.