This year marks the 100th anniversary of the formation of the Soviet Kazakh Republic. Until now, in historiography, August 26 is the date of adoption of the decree of the Central Executive Committee and SNK of the RSFSR “on the formation of the Autonomous Kyrgyz (Kazakh) October 4 – the opening day of the Constituent Congress of Soviets of the USSR was considered the date of formation of the Republic. We consider both dates incorrect. In fact, on October 6, 1920, at the evening session of the Constituent Congress of the Soviets of the KASSR, the first constitutional document “Declaration of the rights of workers of the KASSR” was adopted and the KASSR declared the Republic of Soviets of workers, labor Kirghiz people, peasant, Cossack and red army deputies. The Soviet Kazakh autonomy was the historical basis for the unification of the original Kazakh lands into one Republic.