The article discusses the features of the emergence and spread of sectarian organizations and Old Believer communities in the Azov region in the 19th century. It is shown that the processes of the spread of sectarian organizations century were very active, which is explained by the fact that sectarian organizations had a broad social base and expanded dynamically, despite restrictions from the official government. The laws in force at that time limited the activities carried out by the Russian Orthodox Church in counteracting the process of promoting sectarian teachings at that time. The article illustrates that some of the representatives of sectarianism disguised themselves as Orthodox and compactly lived within the boundaries of church parishes. Proselytizing sectarianism was especially active in the territory of the Yekaterinoslav province by organizations such as the Molokans, Khlysts, Skoptsy, Old Believers, and others. This article characterizes the prevailing political and legal conditions for the spread of the sects, as well as the features of the system of religious relations that have developed in the region. On the basis of archival data, the number of such sects as the Molokans, the Whips, the Old Believers and the Evangelists, etc., was studied. The specificity of religious relations between representatives of different religious groups in the Azov region is analyzed within the framework of a unique phenomenon — a polymodel system of the interfaith relations.