For other uses, see Little boy (disambiguation). Little Boy was the codename for the atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used in warfare.