The article explores the issues of the formation and activities of the prosecutor’s office in the 1920s as an institution of the Soviet state, called upon to exercise supervision over the observance of its laws by all actors of public life, including party and state bodies. The relevance of this topic is determined by the difficulties in the formation of the rule of law and civil society in modern Russia, largely due to the influence of the historical legacy of the Soviet period. It is noted that the introduction of the New Economic Policy (NEP) led to an increase in the role of law in public life, which allowed the prosecutor’s office to strengthen its authority in both the state and among the population. The number of citizens appeals to the Prosecutor's Office of Siberia grew from 12,400 in 1924 to 27,100 in 1925. During the period between 1925-1927 alone, the prosecutor’s office of Siberia initiated over three thousand criminal cases against individual workers of local authorities. However, the later rejection of the NEP, which manifested itself most clearly in the grain procurement campaigns of the late 1920s, essentially meant a return to “military communism”; a system more familiar and convenient for the ruling stratum. The prosecution authorities had to adapt to the Stalinist course, which was aimed at abandoning the legitimacy of the NEP. Sources show that a significant number of prosecutors in Siberia, not ready to accept such violations of the rule of law, were suspended from work. The study of the history of the structures of the prosecutor's office of Siberia in the 1920s clearly demonstrates the origins of the transformation of the Soviet state, which proclaimed itself the democratic power of workers and peasants, while turning into a totalitarian regime dominated by party nomenclature.