Richard M. Sweeney, 58, who retired in 1980 as deputy director of the office of management assistance at the Small Business Administration, died of cardiac arrest Thursday at Suburban Hospital in Bethesda. He lived in Rockville.

Mr. Sweeney came to the Washington area in 1963 to work for the SBA He played a key role in setting up the program for the Service Corps of Retired Executives (SCORE), a group of retired businessmen who serve as volunteer advisers to owners of small and newly established businesses.

After his retirement, Mr. Sweeney became a partner with two of his sons in the Paintmaster's Auto Body Shop in Rockville.

He was born in Kittery, Maine. He interrupted his studies at the Massachusetts Institute of Technology to serve as an officer with the Army Air Corps in World II. He returned to MIT after the war and graduated with a degree in business and engineering. He worked for General Electric and Raytheon in Boston before coming here.

Mr. Sweeney had been a member of the Elks and the Knights of Columbus.

Survivors include his wife, the former Jean Mower, of Rockville; three sons, Brian M. and Mark M., both of Damascus, who were in business with him, and Rory M., of Gaithersburg; a daughter, Sandra M., of Rockville; his mother, Frances Sweeney of Kittery, and a sister, Madene Nichols of Edgecomb, Maine.