The Gehlen Organization or Gehlen Org (often referred to as The Org) was an intelligence agency established in June 1946 by U.S. occupation authorities in the United States zone of post-war occupied Germany, and consisted of former members of the 12th Department of the German Army General Staff (Foreign Armies East, or FHO). It was headed by Reinhard Gehlen who had previously been a Wehrmacht Major General and head of the Nazi German military intelligence in the Eastern Front during World War II.

The agency was a precursor to the Bundesnachrichtendienst (BND or Federal Intelligence Service) which was formed in 1956.

After World War II, Reinhard Gehlen acted under the tutelage of US Army G-2 (intelligence), but he wished to establish an association with the Central Intelligence Agency (CIA). In 1947, in alliance with the newly created CIA, the military orientation of the organization turned increasingly toward political, economic and technical espionage against the Eastern bloc and the moniker "Pullach" became synonymous with secret service intrigues.

According to one report, the Org was for many years "the only eyes and ears of the CIA on the ground in the Soviet Bloc nations" during the Cold War. The CIA kept close tabs on the Gehlen group: the Org supplied the manpower while the CIA supplied the material needs for clandestine operations, including funding, cars and airplanes.^{[citation needed]}

Every German POW returning from Soviet captivity to West Germany between 1947 and 1955 was interviewed by Org agents. Those returnees who were forced to work in Soviet industries and construction, and who were willing to participate, represented an incomparable source of information: a post-war, up-to-date picture of the Soviet Union as it evolved.

The Org had close contacts with East European émigré organizations. Unheralded tasks, such as observations of the operation of Soviet rail systems, airfields, and ports were as important as infiltration in the Baltic States using former Kriegsmarine E-boats, manned by German crews and skippered by Lieutenant-Commander Hans-Helmut Klose [de]. Another mission by the Gehlen Organization was Operation Rusty, which carried out counter-espionage activities directed against dissident German organizations in Europe.

The Org's Operation Bohemia was a major counter-espionage success. By penetrating a Czech-run operation, the Org uncovered another network – a spy ring run by the Yugoslav secret service in several cities in western Europe. The Gehlen Organization was also successful in discovering a secret Soviet assassination unit functioning under the umbrella of SMERSH. An Org informant in Prague reported that the Red Army had been issued an advanced, multi-usage detonator of Czech design but manufactured in a defense plant in Kharkiv. The CIA showed interest. Several weeks later, the Org's couriers presented the detonator, with complete technical data, to the CIA liaison staff at Pullach. Just afterwards, the Czech engineer and his family were smuggled across the frontier into West Germany and on to the United States. By identifying people who suffered under the new communist regimes in eastern Europe, the Org recruited many agents who "wished nothing more than to drive the Bolsheviks from Europe".

In 1948, the Gehlen Organization had an annual budget of US$1,500,000 (inflation adjusted US$20.1 million present day).