In this article, we write about the key principles of decentralization of state power and peculiarities of its realization in conditions of democratic transformation (experience of Ukraine). Decentralization became a real megatrend of the XX and probably XXI centuries (at least in Ukraine). First of all because of the ever-increasing interest of people in the role of civil society and the private sector as the primary partners of the state and local self-government bodies to search for new methods, instruments and approaches to solve local issues at the level of their emergence. Decentralization as a process involves, first of all, restructuring, review of procedures and redistribution of powers to increase the competitiveness of territorial communities, to strengthen democracy and effectively address local issues at the level of their emergence. At the time of globalization, decentralization has become its foundation, as it increases the weight of local rule-making and the importance of relationships at the international, national, regional and local levels through the practical application of the principle of subsidiarity.