Robert R. DeMaio, 61, a Washington area builder and real estate developer since 1952, died Jan. 29 at his Chevy Chase home of amyotrophic lateral sclerosis, also known as Lou Gehrig's disease.

In 1958, he and a brother, Sal DiMaio, formed DiMaio Brothers, Inc. which developed housing communities in Montgomery and Prince George's Counties.

After World War II, Mr. DeMaio had joined his father and brother in the construction business in New York. He and his brother then formed a partnership with Howard and Simon Michnick to build homes on Long Island. The company established a division in Rockville and Mr. DeMaio came here in 1952 to supervise construction of 400 homes in the Silver Rock community in Rockville. The company built more than 2,000 homes, apartments and office buildings in Maryland and Virginia before the partnership was dissolved in 1958.

Mr. DeMaio was born in New York City. He served in the Pacific with the U.S. Navy in World War II.

He had been an active member of the Metropolitan Washington Home Builders Association for 28 years.He belonged to the Manor Country Club.

Survivors include his wife, Estelle, of Chevy Chase; a daughter, Barbara Markwood of Rockville; his brother, Sal, of Rockville; five sisters, Josephine Conti, Sadie Arculeo and Helen Kent, all of Florida, Lucy Pellechio of New York, and Gene Taibbi of Hawaii, and one grandchild.

The family suggests that expressions of sympathy be in the form of contributions to the ALS Society of America, PO Box 5951, Sherman Oaks, Calif. 91403.