Nahum Isaakovich Eitingon, or Naum Isaakovič Ejtingon (Russian: Наум Исаакович Эйтингон, Hebrew: נחום אייטינגון), also known as Leonid Aleksandrovich Eitingon (Russian: Леонид Александрович Эйтингон) (6 December 1899, Shkloŭ, Mogilev Governorate – 3 May 1981, Moscow), was a Soviet intelligence officer, who was sometimes described as a major organizer of Joseph Stalin's state terrorism system. He is the brother of Max Eitingon.
Eitingon, a Belarusian Jew, joined the Cheka in 1920, shortly before his 21st birthday. Along with other Chekists, he took part in numerous operations during the Russian civil war, including the "liquidation" of a number of the more prosperous citizens of the Belarusian town of Gomel. At the end of the 1920s, Eitingon, a polyglot, organized and led an operation producing fake documents which persuaded the Japanese that 20 Russian agents who were working for them had secretly applied to have their Soviet citizenship restored. This ruse resulted in the Japanese executing their anti-Soviet allies.
He was recruited by INO (Soviet foreign intelligence) chief Artur Artuzov to lead the "illegals" program in April 1933.
He was active in Spain in the late 1930s, during the Spanish Civil War and in Belarus during the Second World War. As a high-ranking NKVD officer, Eitingon was responsible for numerous kidnappings and assassinations, even in peacetime.