Activated in June 1943 as a heavy bombardment group. Trained with B-24 Liberators for duty overseas. Moved to Italy, December 1943 – January 1944. Began combat with Fifteenth Air Force in February 1944, operating chiefly against strategic targets until late in April 1945. Early operations included attacks against such objectives as marshalling yards, aircraft factories, railroad bridges, and airdromes in Italy, Austria, and Romania.

The IV Bomber Command is a disbanded United States Air Force headquarters. It was established in September 1941, shortly before the attack on Pearl Harbor to command bomber units assigned to 4th Air Force. Following the entry of the United States into World War II, it flew patrols off the Pacific coast. However, its main efforts soon began organizing and training bomber units and aircrews. It was disbanded at San Francisco, California on 31 March 1944.