Current importance of this investigation has been stipulated by the modern trends in the development of civil society. Differentiated processes of its development, increased significance of certain institutions of the civil society often require not just empirical description of the principal trends of the functions of civil society, but also need theoretical justifications for the methodology of its investigation. With this regard the given article is focused on identifying the position and role of social solidarity within classical sociology that would make it possible to use this heuristic potential in modern practices as well. The principal method of the study is represented by the analysis of classical sociological theories. In the course of the investigation the authors were guided by such methodological landmarks as the general principles of socio-cultural, activity-based, socio-structural and systemic approaches, by the principle of the unity of theoretical constructions and by real social practice. The study considers the concepts of social solidarity developed by the representatives of classical sociology. The suggested approach makes it possible to obtain more comprehensive and profound understanding of the structure and essence of modern civil society. The result of the investigation is represented by the justification of the thesis that modern civil society encompasses social solidarity as an inseparable component which cannot be investigated otherwise than being duly supported by classical sociological theories.