The objective of this paper is to present the most characteristic features of the international system. The author outlined the most important theoretical and practical aspects of both the international system concept and essence as well as pointed to the distribution of power between world powers as the core issue of each international system. In the paper, the author highlighted the evolution of post-Cold War order in the global scale (international global system), particularly the evolution of the United States as the super power and related prognoses regarding more or less probable consequences of this process. The main thesis of this paper says that the post-Cold War international system, dominated by the United States’ superpower position, slowly evolves towards “post-unipolar system” (post-American system). There are many indications that the post-American system will be a multipolar system with a number of centers of power in different regions of the world and the power will be associated with various levels of international relations (multilevel multipolarity). The new system will be based on regional and global powers that will differ in their acquired power and influence, which they will use towards other actors of international relations.