Barney O. Weitz, 70, a retired realtor and long-time Washington resident, died Friday after a long illness at Washington Hospital Center.

Born in Lodz, Poland, Mr. Weitz came to the United States with his family when he was 8 years old. They lived in New York briefly, and then moved to Washington, where Mr. Weitz attended Polk Elementary School and a business high school. He founded the Weitz Coal COmpany, and then changed to the realty business by opening the Weitz Realty Company, which he headed for more than 45 years.

Mr. Weitz was a lifetime member of congregation B'nai Israel and the Tifereth Israel Congregation. He was also a charter member and active worker for the Hebrew Academy of Washington, which his father, Jeremiah Weitz, helped found, Mr. Wetz was also a 32d Degree Mason.

He is survived by his wife Henrietta Weinstein Weitz, of the home in Northwest Washington; brother Joseph, of Miami; daughters Barbara J Holtz, of Silver Spring, and Marilynn W. Cohen, of Potomac; son Alan S. Weitz, of Wasginton; and nine grandchildren.

The family suggests that expressions of sympathy be donated to the Congregation B'nai Israel Building Fund or the Hebrew Academy of Washington.