James L. (Jimmy) DeChard, 59, an amateur and then a professional heavyweight boxer in Washington in the late 1930s and early 1940s, died of a heart attack Wednesday.

He was stricken on the University of Maryland golf course on the College Park campus and was pronounced dead on arrival at the Washington Adventist Hospital.

Mr. DeChard was president of the James L. DeChard Co. Inc., a mechanical contracting firm which he established in 1962. It installs plumbing, heating, ventilating and air conditioning equipment.

He was born in Washington. He became an amateur boxer while in his teens and was the D.C. Golden Gloves heavyweight champion in 1938. A year later, he defeated Tony Novak in a national Amateur Athletic Union bout at the old Griffith Stadium, which was billed as the battle for the amateur heavyweight championships of the United States.

Mr. DeChard later turned professional and won a number of fights. His career was interrupted by service in World War II when he was a physical education instructor in the Navy. He also was troubled by an injured hand and gave up boxing after the war.

Mr. DeChard studied engineering at Catholic University and worked as an estimator for several plumbing firms here before founding his own company.

At the time of his death, he was treasurer of the Washington, D.C., Boxing Hall of Fame. He belonged to the Touchdown Club.

He also was a member of the Mechanical Contractors Association and the Plumbers Union Local NO. 5. He was a fourth degree Knights of Columbus, Washington Council 224 member.

He is survived by his mother Marguerite DeChard, and a sister, Dorothy DeChard, both of the home in Cox, of Mount Rainer, and a brother, William, of Mahwah, N.J.