Clement A. Ducy, 70, a retired economist with the Federal Reserve Board and an economic and management consultant in Washington for almost 30 years, died Aug. 23 at Sibley Memorial Hospital after a stroke. He lived in Washington.

Mr. Ducy, a native of Colorado, moved to Washington in 1929. He was a 1933 graduate of Catholic University. He worked as a staff assistant on Capitol Hill before returning to Colorado in 1935 with the old Public Works Administration as an administrative officer.

He returned to Washington in 1949. He was an economist with the National Production Authority and director of the materials division of the Small Defense Plants Administration during the Korean War. He worked as a consultant until joining the Federal Reserve Board in 1968. He retired in 1973.

Mr. Ducy cofounded the National Young Democratic Clubs of America. He was a former president of the Catholic Youth Organization and founder and chairman of CYO's trust foundation. He was a member of the Cardinal's Committee for the Laity.

Survivors include his wife, Ellen C. O'Brien Ducy of Washington; three daughters, Ellen de Perez of the Dominican Republic, Mary Elizabeth, of Houston, and Patricia C., of Falls Church, and three grandchildren.