The purpose of this study was to research the methodological approaches to the study of interethnic relations and ethno-social processes. The analysis of the literature was conducted in three main areas: 1) the theoretical and methodological issues of organizing the research of inter-ethnic relations, allowing to highlight the current methodological approaches and principles of organizing such studies; 2) studies of ethno-social processes in multiethnic societies, which determined the strengths and weaknesses of different research designs; 3) the current state of inter-ethnic relations in different regions of Russia, which has allowed to develop criteria for determining the areas in which such researches will be most topical. The data systematization and conceptual synthesis method have contributed to the development of a new methodological basis for inter-ethnic relations and ethno-social processes research in modern Russia. The developed methodological basis will allow to conduct a comprehensive, high-quality and timely evaluation of the processes of ethno-social and inter-ethnic relations. Such diagnostics, in turn, will contribute to the effective prevention of interethnic conflicts in multi-ethnic regions of modern Russia.