William Morgan McCormick, 69, a retired Navy rear admiral who became vice president of the Franklin Mint in Philadelphia, died of cancer Saturday at the National Institutes of Health. He lived in Alexandria.

Adm. McCormick, who was born in Perth Amboy, N.J., graduated from the U.S. Naval Academy at Annapolis in 1934. He was a naval aviator in World War II and took part in the Atomic Energy Commission's nuclear weapons tests in the Pacific in the postwar years.

From 1956 to 1958, he was the U.S. naval attache in Rome. He later commanded the carrier task force that picked up the Gemini 4 space shot. His Washington assignments included a tour as assistant director of the Defense Intelligence Agency. Adm. McCormick was commander of Naval air forces in the Atlantic Fleet when he retired in 1968.

A year later, he became a vice president of General Consultants Inc. in Washington. In 1969, he was named vice president for international monetary contracts of the Franklin Mint. He retired in 1977 and returned here.

Adm. McCormick was a member of the New York Yacht Club and the Army Navy Country Club.

Survivors include his wife, the former Lalla Jane Cary of Alexandria; a daughter, La Comtesse Tristan du Parc Locmaria of Paris; two sons, James Watt of San Francisco, and John Thomas of Aspen, Colo., and two grandchildren.