Frederick L. Townshend, 50, a publications officer with the Food and Drug Administration who had worked for the agency since 1961, died of cancer Tuesday at the Washington Hospital Center.

He began his government career with the Central Intelligence Agency as an editorial clerk in 1948. After a stint with the Defense Department as a personnel officer, he returned to the CIA where he was a senior publications editior from 1953 to 1957. Mr. Towshend worked for a time in private industry before joining the FDA.

He was active in benefits for St. Thomas Episcopal Church in Croom, Md. For nearly 20 years he had managed the church's annual tobacco barn antique show, which is held in Upper Marlboro and has grown into one of the largest of its kind on the East Coast. He also had been a member of the church's vestry for many years.

He was a member of Ducks Unlimited, a wildlife conservation organization.

Mr. Townshend was a native and resident of brandywine, Md., and was a veteran of the Marine Corps.

Survivors include his wife, Audrey K., a son, Peter, and four daughters, Laura, Sarah, Lisa, and Amy Townshend, all of Brandywine; another daughter, Barbara Tauber of Park Ridge, Ill.; four sisters, Harriette T. dViets of Fredericksburg, Va., and May T. Cooksey, Thelma O. Watson and Nellie Oliver, all of Brandywine, and four brother, Woodrow W., of Brandywine, Julius K., of Battle Creek, Mich., Thomas H., of Baltimore, and John B., of Fairbanks, Alaska.