The article focusses on the problem of determining and expressing the subject matter of Russian constitutional law. In author's opinion, the discussion is still not finished not only due to inconsistency of scientific approaches and conceptual constructions, but also Russian constitutional practice. The author highlights the variety of approaches in course books. There is a tendency to include in the area of constitutional regulation an extremely wide range of social relations functioning in all fields (political, economic, social, spiritual). According to the author, despite the value judgements concerning approaches to the definition of the subject matter of constitutional law, the positivist legal method prevails. The author considers methodological approaches established in the domestic doctrine of constitutional law. The author highlights the importance of the concept of constitutionalization and its role in localization of the subject matter. The author substantiates the constitutional law subject matter on the basis of the functional purpose of the branch in question, the spheres of constitutional regulation with due regard to the characteristics of constitutional law development.