Dr. Alex Horwitz, 78, a well known Washington surgeon and professor emeritus of clinical surgery at George Washington University Medical School, died Tuesday at his home in Washington. He suffered from a heart ailment.

He established a practice here in 1923, and maintained it for nearly a half-century. He joined GWU teaching staff as an instructor in surgery in 1930, and became professor emeritus in 1972.

Dr. Howitz was born in Russia. He and his family immigrated to Elmira, N.Y., when he was 7. They then moved to Washington, where his father, the late Moses Horwitz, became a rabbi.

He was graduate of old Central High School, George Washington University, and its medical school. He had worked his way through college both as a Hebrew tutor and Sunday school teacher, and received a special award for achieving the highest academic record in class as an undergraduate and a medical student.

Dr. Howitz completed four years as a fellow in surgery at the Mayo Clinic in Rochester, Minn., before establishing a practice here. In 1959, the Alec Horwitz Prize was established at GWU Medical School. It is awarded annually to the senior showing the greatest proficiency in surgery.

He had been named Man of the Year in 1958 by the Jacobi Medical Society of Washington. He was a member of the D.C., Medical Society, the American Medical Association and the Southeastern Surgical Congress.

Dr. Howitz was a founder and past president of the Washington Academy of Surgery and a life member of the American College of Surgeons.

He had served many years on the board of directors of the Jewish Social Service Agency, for which he set up a medical panel and served as its chief. He also was a consultant in surgery to the old Hebrew Home for the Aged and a member of the executive committee of B'nai B'rith Argo Lodge and the board of directors of the Brandeis Zionist Organization of Washington.

A veteran of World War I, when he served briefly in the U.S. Army, Dr. Horwitz had been post surgeon for Post 58 of the Jewish War Veterans.

He is survived by his wife, Jean Himmelfarb, of the home; a son, Dr. Norman H., of Chevy Chase; a daughter, Mrs. Jack Kushner, of Annapolis; a brother, Abraham, of Tuscon, Ariz., and five grandchildren.

The family suggests that expressions of sympathy may be in the form of contributions to the Alec Horwitz Memorial Lectureship Fund at George Washington University.