The article traces price development in USSR economy over the last two decades of its existence and distinguishes factors that shaped this development. The novelty of the research consists in a detailed analysis of prices changes in the course of twenty years and factors that produced an impact upon this. In spite of the basic negation of the very possibility of inflation under socialism, it did exist in various forms essentially over the whole socialist period, but became much more expressed starting with 1970s. Many factors determining it are still in effect till nowadays.