This paper is devoted to the issue of acceptability of defining religion classes as a compulsory subject in public schools run by religious legal persons. However, while taking into account the achievements of the ecclesiastical law doctrine, the author analyzes this issue from the point of view of the administrative law and indicates the possibility of appropriately applying to this case the regulations pertaining to public establishments and the special institutional governance. In realizing the established research goals the author considers such issues as a school as a public establishment, requirements regarding running public schools, the legal character of statutes of schools or the unique characteristics of the schools run by denominations having legal personality. As a result of the conducted legal analysis the author concluded that when taking into consideration the voluntariness of attending religion classes it is acceptable to, under the special institutional governance, recognize religion classes as a compulsory subject in the public schools run by entities other than local self-government units. However, such possibility exists only when there is no catchment area established for such schools which results in the voluntariness of selecting such schools as a place of realization of compulsory schooling as well as in the prospect of selecting a different public school in which parents or pupils of legal age may resign from attending religion classes.