The pioneers of Sambo were Viktor Spiridonov and Vasili Oshchepkov. Oshchepkov died in prison as a result of the political purges of 1937 after accusations of being a Japanese spy. Oshchepkov spent much of his life living in Japan and training judo under its founder Kano Jigoro. The two men independently developed two different styles, which eventually cross-pollinated and became what is known as Sambo. Compared to Oshchepkov's judo-based system, then called "Freestyle Wrestling", Spiridonov's style was softer and less strength dependent. This was in large part due to Spiridonov's injuries sustained during World War I.
Anatoly Kharlampiev, a student of Vasili Oshchepkov, is often considered the founder of Sport Sambo. In 1938, it was recognized as an official sport by the USSR All-Union Sports Committee.