Herbert Brooke Belmear, 66, who retired in 1978 as an employe relations specialist with the Library of Congress, died of cancer Sunday at the Washington Adventist Hospital. He lived in Silver Spring.

He joined the library staff in the old card division in 1941 and returned there after serving with the Army in World War II.

Mr. Belmear later worked as a filer in the catalogue maintenance division, a cancellation clerk in the order division, an accessioner, and a supervisor of the order division's continuations unit. He was named an employee relations specialist in 1971.

He had served as a fair employment practices officer for the library and had earned the library's Special Achievement Award.

Mr. Belmear was born in Bardstown, Ky., and grew up in Louisville. He earned a degree in American history from the University of Louisville and took graduate work at the University of Chicago.

He is survived by his wife, Edith M., of Silver Spring; a daughter by a previous marriage, Audrey Ann Belmear of Hazlet, N.J.; a stepdaughter, Margaret Jackson of Columbia, Md.; two stepsons, William and David McCloud, of Silver Spring; his stepfather and his mother, Mr. and Mrs. Max Sheppard of Washington, and a brother, Horace, of Morgantown, W. Va.