Introduction. The article is devoted to the peasant population of the Upper and Middle Podonia in the 17th century. For the first time an attempt is made to make an extensive comparative analysis of the dynamics and number of peasants in the second half of the 17th century in such southern Russian counties as Voronezh and Yelets. Methods and materials. The methodological basis of the study is based on the fundamental principles of historical cognition, used in the national historical science in the study of socio-economic processes of society and its structural components: historicism, objectivity and systematicity. To consider the issues related to the peasant population of the south of Russia in the 17th century and its number, we use general scientific, special-historical and interdisciplinary methods, such as descriptive-narrative, historical-genetic (historical), problem-chronological, comparative-historical, statistical methods, modelling. The research was based on the most important mass sources on the history of land ownership and rural population - census books of 1646 and 1678. Results. The author of the article comes to the conclusion that the peasant population during the second half of the 17th century remained the main mass of rural inhabitants of the counties under consideration. Their distribution on the territory of Voronezh and Yelets counties was uneven and often depended on the degree of protection of a village or hamlet from Tatar raids. Conclusion. Despite the fact that the number of peasants was continuously growing, they were still catastrophically insufficient for the intensive development of manorial land ownership, which was necessary for the defence of the district from attacks of nomadic ethnic groups and economic support of the fortress city. This situation inevitably led in the second half of the 17th century to the growth of the single-tenant economy.