The question of the place of family law in the Russian legal system is traditionally one of the most controversial in legal science. This discussion acquired special acuteness and theoretical depth in the works of Russian jurists of the 19th and early 20th centuries. During this period, the formation of the doctrinal foundations of Russian law took place. Defining the boundaries of family law was complicated by the close intertwining of secular principles and norms of church law. The analysis of their scientific heritage allows us to trace the evolution of views on the nature of family relations, due to the search for a balance between canonical traditions, the needs of developing social relations and the peculiarities of the emerging secular legal system. The purpose of this study is to systematize the main approaches of pre-revolutionary scholars to determining the place of family law in the system of Russian law and to identify the key arguments of supporters of various concepts. The study analyzes the scientific discussion about the place of family law in the system of Russian law, which unfolded in the XIX — early XX centuries. It is noted that the general theoretical dispute about the legal nature of church law has naturally led to the question of the nature of the interaction of church law and state law norms in the regulation of marriage and family relations.