The author considers the problem of social service of the Russian Orthodox Church at the end of the 20th – beginning of the 21st centuries, using the example of the Kostroma diocese. The relevance of the problem arises from a number of factors. First, the need for an understanding of the social role of the Russian Orthodox Church, as one of the most important structures influencing an active public position in Russia. Secondly, by strengthening its practical importance, since in the post-Soviet period the role of the Church in our country has increased significantly. Third, in the conditions of a permanent socio-economic crisis and a drop in the standard of living of the population, the public demand for church charitable structures is increasing. This article highlights the main directions of the social activities of the Orthodox clergy in the region under consideration. On the basis of archival materials, the history of the formation of church institutions that contributed to the expansion of social service in the Kostroma diocese is traced. Special attention is paid to the study of the experience of practical interaction between the state and the church in providing assistance to the poor. The findings can be used in the social work of the Russian Orthodox Church at the present time.