The article analyzes the state and trends in the development of the military-industrial complex of the USSR in 1939–1941. During the period under review, the country's leadership paid considerable attention to the development of the main branches of the defense industry. The aviation and tank industries are becoming a priority. This was largely due to the fact that it was in this area that the potential enemy of Germany managed to get ahead. In 1939, the task was set not only to increase the capacity of the Soviet aviation and tank industry, but also to create new types of aircraft and tanks. This task was completed. However, the share of new aircraft and tanks by June 1941 was 17.2 %, and even less tanks-10 %. Artillery weapons received serious development, but the role of small automatic weapons for infantry was clearly underestimated, which was undoubtedly a major mistake. By the beginning of the Great Patriotic War, a fairly large-scale and developed multi-industry militaryindustrial complex was created in the USSR, capable of producing almost all types of weapons. By this time, qualified personnel of workers, engineers and managers were formed, and a fairly effective management system for the military-industrial complex was created. At the same time, many factories of the defense industries were not yet completed, and those built were slowly being mastered. The created defense potential in the pre-war years became the material basis for victory in the future war.