In the USSR, the first Olympiads were held in 1934 in Leningrad and in 1935 in Moscow. The initiators of their holding were the largest Soviet mathematicians. Before the war, Olympiads were held annually and quickly gained popularity. In a number of universities, school mathematics circles began to work. After World War II, mathematical Olympiads became traditional for many cities of the Soviet Union, they were held by universities and pedagogical institutes together with public education bodies.