Margaret M. Bennick, 62, who retired in 1978 after serving for five years as a psychiatric nurse at the D.C. Rehabilitation Center for Alcoholics at Lorton, died of cancer Thursday at DeWitt Army Hospital at Fort. Belvoir. She lived in Springfield.

Mrs. Bennick was a registered nurse at DeWitt Hospital from 1963, when she settled in Springfield, to 1973.

She was born in New York City and graduated from St. Mary's School of Nursing in Brooklyn. During World War II, she was a lieutenant in the Army Nurse Corps on assignment at More General Hospital in Swannanoa, N.C. She was discharged in 1945.

After the war, she accompanied her husband, Bernard A. Bennick, on Army assignments to Japan and Panama, where she continued to work as a nurse. They also were in Puerto Rico.

Mrs. Bennick was a Red Cross volunteer and a member of the Senior Citizens group of St. Lawrence Catholic Church in Alexandria.

In addition to her husband, now a retired Army colonel of Springfield, she is survived by two daughters, Louise Eskay of Gaithersburg and Patricia Bennick of Alexandria; a son, Bernard A. Jr., of Ocean City, Md.; a sister, Evelyn Clanny of The Bronx, and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Northern Virginia Chapter of the American Cancer Society.