Retired Army Lt. Col. Alexander S. Mikhalevsky, 58, the director of statistical research for the Pharmaceutical Manufacturers Association and an interpreter at the post-World War Ii Potsdam Conference, died of cancer Sunday at the Walter Reed Army Medical Center.

Born in Yugoslavia, Col. Mikhalevsky came to this country with his parents as an infant. He was reared in New York City, graduated from Wagner College, enlisted in the Army in 1943 and was commissioned in 1945. He was assigned to Berlin.

Because he was fluent in Russian, French and German, he acted as an interpreter at the Potsdam Conference, which was attended by President Truman, Prime Ministers Winston Churchill and Clement Atlee, and Marshal Stalin.

Col. Mikhalevsky later served at posts in this country and in Japan, Laos, and Morocco. He retired in 1968 and moved to Alexandria.

He was head of research for the American Association of Medical Clinics before joining the Pharmaceutical Manufacturers Association in 1972.

Col. Mikhalevsky was a member of the Retired Officers Association and the Military Order of the World Wars.

Survivors include his wife, the former Helen Leslie, and a daughter, Helen, both of Alexandria; another daughter, Lisa Morris of Fairfax; a son, Andrei, of Atlanta; his father and stepmother, Serge N. and Olga Mikhalevsky of Springfield; a brother, Navy Capt. Nicholas Mikhalevsky of Arlington, and a grandchild.

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