The article analyzes the evolution of relationships between local authorities and Russian Orthodox communities in the Baikal region in the 1920s -1930s: from neutrality to open confrontation. Self-sufficiency of Irkutsk and Transbaikalian dioceses, their dominant position as regards the number of followers and clergy, opulence of church property and other factors determined the directions of state policy, the full-fledged implementation of which in the Baikal region commenced in 1920. The following key aspects of relationships between state and church in the 1920s – 1930s should be outlined: reorganization of eparchial administrative bodies, nationalization of property, forfeiture of church valuables, renovationist schism, registration of religious communities, economic pressure, closure of religious buildings, repressions against the clergy and laymen.