The process of Europeanization that is the adjustment of the national legal regulations, intstitutions and decision making patterns to the European political practice leads to the significant transformation of the national political systems. In the horizontal dimension of the state institutions this concerns primarily the relationship between the executive and the legislative powres whereas in the vertical dimension this influences the relationship bewteen the central state and the regions or provinces. The paper examines the source and durability of the Europeanization process in three Central and Easterna European countries, in Poland, Hungary and Czech Republic. Focus is primarily laid upon the institutional adjustments.