Abstract: The article is devoted to the study of the theoretical and methodological foundations of the research field of religious conservatism. By itself, religious conservatism as a phenomenon of public life and social structure, since its inception, has had a great influence not only on the religious sphere of society, but also on the political and even economic spheres. The modern research field of religious conservatism is quite diverse, there are a large number of different directions and schools in it, but most of them borrow their methodological foundations from a certain number of classical works on sociology, formed within the framework of mainstream sociological secularism. In this regard, secularism attitudes continue to be reproduced quite often in modern sociological science. The purpose of this work is to examine the early, fundamental theoretical and methodological positions created in classical sociological works on the topic of religious conservatism as a social structure and social phenomenon. To achieve the goal, it was necessary to solve the following tasks: 1) To characterize the works of the early stage of the study of religious conservatism in sociology; 2) To identify and characterize the theories of society in which the main works were created; 3) To define the concept of religious conservatism as a social phenomenon or social structure; 4) Describe the impact of these concepts on further sociological discussion. The research materials were theoretical studies by foreign authors devoted to the conceptualization of the theme of religious conservatism. The research methodology is based on secondary analysis. The results revealed the main patterns of the theoretical foundations of religious conservatism in the works of the classics of sociology.