The article explains the role of small and micro businesses in the Russian economy. The study demonstrated the positive impact the introduction of a simplified tax system for the development of this sector. This paper gives the concept of a simplified system of taxation applicable in the Russian Federation and the Commonwealth of Independent States. The study highlights the distinctive features specific to the special tax regime. The article discusses the pros and cons of the transition of organizations and individual entrepreneurs with the general regime of taxation on the single tax payment when applying the STS. On the basis of essentially clarify and functional features of the simplified taxation system its own definition has been formed.