Mayno Webb Sierra, 67, a retired employe of the Department of the Army and a longtime resident of Silver Spring, died of respiratory failure June 5 in Palmdale, Calif. She had Guillain-Barre syndrome, a virus infection.

Mrs. Sierra, who was born in Hickory, N.C., came to Washington in 1941 to work for the Treasury Department. Shortly after the United States became engaged in World War II, she joined the Office of Strategic Services (OSS), a predecessor of the Central Intelligence Agency. At the end of the war, she joined the Army Signal Corps.

She worked as a civilian employe of the Army until retiring in 1971 as a member of the staff of the Pentgon communications center. She then spent six years as a secretary with Vitro Laboratories in Silver Spring until 1976, when she retired for reasons of health.

Mr. Sierra moved to Palmdale to live with a son, Jim Barker, in 1979.

Her marriages to Theodore R. Barker and Army Sgt. Willie M. Sierra ended in divorce.

In addition to Mr. Barker of Palmdale, Mrs. Sierra's survivors include a second son, F. M. Webb of Salt Lake City; a brother, Arthur W. Webb, of Kensington; eight grandchildren, and one great-grandchild.