The article attempts to identify the major factors of party system nationalization in contemporaryRussia. The concept of nationalization is treated as the nationwide participation in elections andterritorial voting homogenization, which allows to study the formation of national parties participatingin the process of political competition within nationwide standardized patterns of electoral behavior. Thestudy is focused on national (2016) and subnational (2012-2016) parliamentary elections (proportionalrepresentation). The author introduces the national-subnational covering index, which covers electionparticipation strategies of political parties at different territorial levels. The measuring shows a significantvariation in electoral participation of the parties across the territory, what can be explained by the level ofthe institutionalization (parliamentary / non-parliamentary) as well as their durability. Also, statisticalanalysis has been carried out with data concerning voting homogeneity of the State Duma 2016 elections(according to Party Nationalization Score by Jones-Mainwaring) used as sample. Principal componentanalysis has revealed that the voting nationalization structure is quite compact and similar to the structureof electoral competition where “United Russia” occupies a separate position from all other parties in theelectoral space (so-called “structural domination”). On the other hand, it is also important to considerthe cleavage between the federal parliamentary parties and the non-systemic opposition plus the mostsuccessive spoilers. For instance, the regression analysis reveals the importance of regional politicalfactors like the governors’ ability to consolidate regional elites delivering votes in high levels of territorialhomogenization. At the same time the radical opposition remains marginalized, being forced to deny participating in regional electoral campaigns.