Louise Moore Singleton, 61, president of Century 21-Singleton Realtors, who was active in the Northern Virginia Board of Realtors, died of cancer Saturday at her home in Falls Church.

Mrs. Singleton and her husband, Jimmie H. Singleton, a former pilot and captain with Eastern Airlines, moved to Falls Church in 1959. They started their real estate firm in 1963 and ran it together until Mr. Singleton's death in 1974. Mrs. Singleton remained the president of the company for the rest of her life.

She was born in Monroe, La., and grew up in Spartanburg, S.C. She later lived in Jacksonville, Fla., and there she met her husband. They lived in various parts of the United States and in Germany before moving to Falls Church.

Mrs. Singleton was a director of the Northern Virginia Board of Realtors. She also served on the organization's membership, awards, housing, ethics and professional standards committees. In 1973, she was elected president of its Executives Club, the first woman to hold that position. She also was a member of the Falls Church Woman's Club.

Survivors include four sons, Philip M., Joseph E. (Win) and Stephen M., all of Falls Church, and Jimmie H., of Blanco, Tex.; one daughter, Patricia S. Reiser of Reston; one brother, retired Air Force Lt. Gen. Joseph H. Moore of San Antonio, Tex.; one sister, Marjorie M. Armstrong of Republic, Mo., and two granddaughters.

The family suggests that expressions of sympathy be in the form of contributions to the Hospice of Northern Virginia, 4715 N. 15th St., Arlington, Va., 22205.