Adelaide C. Baum, 71, who was active in church and civic organizations in Falls Church for more than 20 years, died of pneumonia May 10 in Norwich, England, while on vacation.

Mrs. Baum was an organizer of the Falls Church unit of the League of Women Voters in 1951. She later served as president of the group and on the league's Virginia state board.

She was named head of a citizens' advisory board on housing policy by the Falls Church City Council in 1973, and received an award in 1976 from the council for her work.

Mrs. Baum was a member of St. James Catholic Church, where she chaired the social action group in the early 1960s. She later was a member of the diocesan committee on social action.

She was born in Havehill, Mass., and moved here in 1933. She worked for a time as a government clerk, and then as a statistician from 1936 to 1945, first for the Bureau of Labor Statistics and then the U.S. Civil Service Commission.

She is survived by her husband, Robert D., of the home in Arlington; a son, Clayton, of Brunswick. Maine; a daughter, Caroline, of Washington, and a brother, William Chaisson, of Springfield, Mass.

The faimly suggests that expressions of sympathy be in the form of contributions to the Campaign For Human Development, 1312 Massachusetts Ave. NW.