The article investigates the development of informal employment in the Russian economy in the beginning of the XXI century. An attempt was made to identify the factors that influence on extension of informal employment, not only in the regions but also in the whole country. For this purpose of the subjects of the Russian Federation were grouped in terms of the size of informal employment. The correlations between the indicators of the level of development of the regions and the size of informal employment in each subject of the federation, as well as at the state in general were determined. These correlations are studied both in the short and in the long run.Analysis of factors influencing on the extension of informal employment in different regions of the Russian Federation and in the country as a whole in the short term, carried out on the material of 2012 year, confirmed de Soto's idea of a compelled nature of informal employment.The further analysis showed that the relations between the studied parameters obtained in the short term, often not confirmed in the long term, and sometimes are opposite in nature. This fact became the subject of study in this article. It turned out that in conditions of the economic growth informal employment is a complementary benefit to employment in the formal (legal) economy; that informal employment is to some extent a consequence of the increase in economic well-being of the population, a consequence of the growth of the formal sector. The authors tried to find out in this article why it happens in modern Russia.