Waldemar P.J. Onoszko, 69, a retired lieutenant colonel in the Army and an official of the Central Intelligence Agency, died of cancer Tuesday at Walter Reed Army Medical Center.

Col. Onoszko was born in St. Petersburg (now Leningrad), Russia. He and his family left the country in 1919 during the civil war that ended with the victory of the Communists and the consolidation of the Soviet Union. They spent four years in Constantinople (now Instanbul), Turkey, and then moved to New York City. Col. Onoszko attended the Pratt Institute of Technology and Columbia University.

In World War II, he enlisted in the Army and later was commissioned. His assignments included duty in Iran, where he served as a liaison officer with SOviet forces, and, after the war, in Berlin.

He joined the CIA in 1954. and received various assignments in this country and abroad. In 1968, he retired from the CIA and also from the Army Reserve, in which he had kept a commission. He continued as a consultant for the CIA until 1976.

Col. Onoszko was president of the Parish Council of St. John the Baptist Russian Orthodox Church.

Survivors include his wife, Olga, of the home in Falls Church, and ason, Capt. Peter W.J. Onoszko, also of Falls Church.