Constituted as 464th Bombardment Group (Heavy) on 19 May 1943 (activated 1 August). Activated as a B-24 Liberator heavy bombardment unit; assigned to II Bomber Command for training. Primarily trained in Idaho and Utah received deployment orders for the Mediterranean Theater of Operations (MTO) in February 1943. Deployed to Southern Italy in February 1944; entered combat in April, being assigned to Fifteenth Air Force 55th Bombardment Wing. Air echelon training for a few weeks in Tunisia before joining the remainder of the group in Italy.