Charles E. McCreedy Jr., 59, a senior physical security specialist with the dignitary protective division of the Secret Service, died at George Washington University Hospital Monday of an abdominal aneurysm. He lived in Alexandria.

Prior to joining the Secret Service in 1968, Mr. McCreedy was a chief master sergeant in the Air Force and was in charge of presidential aircraft security at Andrews Air Force Base. In that job, which he held from 1959 until his retirement from the military in 1968, he was responsible for the security of Air Force One, the presidential aircraft.

In the course of his career with the Secret Service, Mr. McCreedy was assigned to political conventions and presidential inaugurations in 1972, 1976 and 1980. He also attended 12 different sessions of the United Nations General Assembly and such special events as the signing of the Panama Canal Treaty.

He supervised identification control, aircraft protective surveys and other security measures for presidents, foreign dignitaries and other persons protected by the Secret Service.He was a senior physical security specialist at the time of his death.

Mr. McCreedy, who was born in Troy, N.Y., served in the Army in the Pacific during World War II. After the war, he returned to civilian life briefly, and then enlisted in the Air Force. He served in Korea during the conflict there and in West Germany as well as at various posts in the United States.

His military decorations included the Legion of Merit and two Air Force Commendation medals.

He was a member of the International Association of Chiefs of Police and the FBI National Academy Associates.

Survivors include his wife, Betty J. McCreedy of Alexandria; two sons, Stephen R., also of Alexandria, and Wayne C., of Houston; one daughter, Laurel A., of Alexandria, and his mother, Mrs. William Hobbs of St. Petersburg, Fla.