Bernard J. Long, 68, a Washington lawyer for more than 30 years and a former resident in Potomac, died Tuesday in his Sarasota, Fla., home following an apparent heart attack.

He worked as an assistant U.S. attorney in Washington for four years before joining the old Bureau of Internal Revenue as a trial counsel in 1943. He later maintained a private practice in tax law before retiring in the early 70s.

Mr. Long was a native of Leavenworth, Kan., and came here at an early age. He attended Eastern High School and earned a law degree at Georgetown University.

After retiring, he moved to Rehoboth Beach, Del., where he was a volunteer public defender. He moved to Florida about two years ago.

He had belonged to the Congressional Country Club.

He is survived by his wife, Frances E., and four daughters, Margaret A., Theresa L., Joanna, and Elizabeth D., all of the home; four other daughters, Mary Leahy, of Crofton, Md., Patricia Johnston, of Nashville, Tenn., Elaine T., of New York City, and Rosemary of Washington; five sons, Bernard J. Jr., of Washington, Dr. John M., of Bangor, Maine, Joseph E., of Sterling Park, Va., and Francis B. and Stephen J., both of Sarasota; a brother, Dr. John A., of Chevy Chase, and 11 Grandchildren.