George Boles McManus 69, a retired senior administrator with the Central Intelligence Agency, died of a viral infection of the brain Saturday in the New England Medical Center in Boston.

Mr. McManus worked for the agency from the time it was founded in 1947 until retiring in 1970. He held posts in Washington and abroad.

During the 1960s, he was special assistant first to Adm. William Raborn, during his stint as director of Central Intelligence, and then to Adm. Rufus Taylor, who was deputy director of Central Intelligence from 1966 to 1969.

After retiring from the agency, Mr. McManus lived in South Africa for three years before moving to Yarmouth Port Mass., in 1973. He had lived in McLean for many years.

Mr. McManus was a native of Arlington, N.J., and a 1931 graduate of the U.s. nAval Academy at Annapolis. He earned a master's degree in business administration at Harvard University in 1933.

He was a banker in New York City before being called to active duty with the Navy in 1939. He was a liaison officer with the British Navy and an intelligence officer during World War II.

He attained the rank of commander and was assigned to the old Central Intelligence Group in Washington before retiring from active duty and joining the CIA.

Survivors include his wife of 35 years, the former Lyndsay Normand, of Yarmouth Port; two sons, Lindsay, of New York City, and Timothy, of Frankfort, Germany; a daughter, Gillian McManaus of Boston; his stepmother, Dr. R. Louise McManus of Falmouth, Mass., and five sisters, Madeleine Frankenhauser of Falmouth, Catherine Myers of Wilmington, Del., Anna McPaden of Seattle, Laura Lockhart of Littleton, Col., and Joan Lawrence of Newton, Mass.

The family suggests that expressions of sympathy be in the form of contributions to the endocrine research fund at the New England Medical Center in Boston.