© 2015 by the author(s). The urgency of the problem under investigation is caused by its being poorly studied in the national historiography. It is devoted to one of the main features distinguishing the Polish-Lithuanian Tatars from others - religion which they kept from the moment of emergence in the Grand Duchy Lithuania, further the Polish-Lithuanian Commonwealth. It was the sphere which is most attracting attention. Particular attention is paid to the peculiarities and specific character of the religious life of the Polish-Lithuanian Tatars, the disclosure of the activities of religious gmina - dzhemat that emerged in the XIV-XV centuries, mosques, construction of which began almost since "osadnichestvo" of Tatars, the place and role of the mullahs as authoritative, educated people and who had a great impact on the daily lives of their parishioners, the description of existing peculiar rituals associated primarily with the three most important moments of life: birth, marriage and death, Tatar cemeteries usually located at the mosques or at high hillocks, waqfs, and so on. This article is based on the basic principles of historical knowledge: the historicism and objectivity, allowing to provide scientific approach to the analysis of the historical processes happening in life of the Polish-Lithuanian Tatars. Materials of the article can be of interest to students, masters, graduate students, teachers specializing on Islam history, for those who are engaged in its studying in Eastern Europe.