John J. Heimburger, 70, a retired chief counsel of the House Agriculture Committee, died of cancer Sunday at the Morton F. Plant Hospital in Clearwater, Fla.

Mr. Heimburger was born in Fulton County, Ind., and attended DePauw University in Greencastle, Ind. He came to Washington in 1929 to attend George Washington University, from which he graduated in 1931. He later earned a law degree at National University Law School, now part of George Washington University.

During his student days and later in the 1930s, Mr. Heimburger was a Capitol Policeman and an employe of the National Park Service. During World War II, he was chief of the press section of the Office of Civil Defense.

He began his career on Capitol Hill in 1947 as counsel of the House Agriculture Committee. He rose to be chief counsel and held that position when he retired at the end of 1966. He moved to Clearwater about 1972.

His wife, the former Eva Marshall Monk, died this year.

Survivors include a daughter, Lucinda Gordon of St. Genevieve, Mo.; three brothers, Albert, of Zionsville, Ind., Wallace, of Indianapolis, and Wendell, of Lafayette, Ind.; two sisters, Rowena Pelz of East Thetford, Vt., and Alice Dubbs of Indianapolis, and two grandchildren.