Ammie A. Muir, 85, a former librarian with the D.C. Public Library and the Department of Labor and a lifelong resident of the Washington area, died of cardiac arrest Sunday at The Hermitage in Northern Virginia in Alexandria.

Mrs. Muir was born in Washington and graduated from Eastern High School and the old Wilson Normal School, where she received a degree in library work. She began her career with the D.C. Public Library while still a student and continued to work there until 1929, when she married Hugh H. Muir, a colonel in the Army Reserves and an official of the Government Printing Office.

During World War II, Mrs. Muir went to work as a librarian for the Labor Department. She remained there until her retirement in 1955.

Mrs. Muir was a longtime member of the Chevy Chase Presbyterian Church and then of the Wesley United Methodist Church. She lived in Washington until 1973 and had been a resident of The Hermitage in recent years.

Her husband died in 1970.

Survivors include a son, Hugh O. Muir of Vienna, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to The Hermitage In Northern Virginia, 5000 Fairbanks Ave., Alexandria, Va., 22311.