In the article grounded the role of decentralization of power and administration in formation the principles of quality content update state influence on social processes of regional systems. Generalized modern theoretical approaches to the consideration of these issues in the theory of public administration and defined the meaning and form of decentralization, its individual components, types and models of implementation. Two  наmain aspects of decentralization of power: separation of authority and responsibilities between the central, regional and local government, and the empowerment of citizens’ participation in solving political, economic and social problems were underlined in the article. Based on the theoretical analysis proved that the implementation of decentralization in the system of public administration of the social development of regions should be carried out in four main areas: institutional (improvement of the organizational structure of public administration of the social development of regions, a clear definition of authorities, organizations and institutions empowered to solve social issues of local significance); functional (statutory definition and delineation of functions and powers of all subjects of management activities on ensuring social development of regional systems, taking into account the principle of subsidiarity); infrastructure (modernization of social service that can ensure their availability and proper quality) and financial (improvement of financial mechanisms to ensure the objectives of social development of the territories). However, each of these areas should be realised in the context and taking into account national reforms practice of public authorities and the establishment of effective local governance in Ukraine.