Prior to the formation of the OSS American intelligence services had been conducted on a ad-hoc basis by the various departments of the armed forces with no overall direction or control (for example the Army and the Navy had separate code-breaking departments (Signal Intelligence Service and OP-20-G) that not only competed but refused to share break-throughs, the original code-breaking operation of the State Department, MI8 run by Herbert Yardley, had been shut-down in 1929 by Secretary of State Henry Stimson because "gentlemen don't read each other's mail"). President Franklin D. Roosevelt was concerned about American intelligence deficiencies. He directed William J. Donovan, a New York lawyer, to draft a plan for an intelligence service.
The Office of Strategic Services was established in June 1942 to collect and analyze strategic information required by the Joint Chiefs of Staff and to conduct special operations not assigned to other agencies. During the War, the OSS supplied policy makers with facts and estimates but the OSS never had jurisdiction over all foreign intelligence activities - the FBI was responsible for intelligence work in Latin America, and the military jealously guarded their areas of responsibility.
In October 1945 the OSS was abolished and its functions transferred to the State and the War Departments.