It is the phenomenon of dominant party in transitional societies that is considered in the article: the dominant parties’ common features, their main types and their functions in a given political system. In such comparativistic context, the author presents specific characteristics of the dominant parties in the post-Soviet states (he distinguishes them as a specific type, suggesting to raise the journalistic cliche “party of power” into the status of a political-science term, in order to bring it out). Further on, the author retraces in detail the evolution, the programmatico-political positioning and the functions of the “United Russia” party and comes to the conclusion that the tasks of Russia’s modernization demand qualitative renewal of this party.