This Thesis answers the question: how does nationalism affect democratization in Eastern Europe? The contemporary European tendencies are showing interesting changes from this aspect. Twenty-five years after the collapse of the Soviet Union, the post-communist Eastern European countries went through a period of contradictory democratization transition. There have been several changes within institutional systems as well as on the level of political culture. However, the Eastern European region still holds certain democratic shortages. The tendency of rising nationalism and anti-democratic populism in the post-communist countries is not a unique phenomenon. The expansion of right wing governments shows correlation with the increasing EU skepticism and anti-democratic populism. At the same time the fast growing far-right parties and extremist movements are enjoying concerning levels of popularity for their anti-elitist, ethnic-based discriminative views and anti-Semitism. The shaken confidence in democratic institutions and the neo-liberal economic system drives many voters to extreme directions. This tendency of raising nationalism questions the effectiveness of the democratic consolidation in the post-socialist countries. According to the case studies it cannot be stated that the raising nationalism harms the democratic transition. Many of the cases pointed out that nationalism and democracy mutually affect and form each other. Since their multiple interconnections the two phenomena cannot be analyzed individually. Both tendencies are dependent variables of complex social, economical and political processes. In many cases nationalism and right-wing populism is also a consequence of the post-communist liberalization process. The young democratic systems are still lacking the experience of reacting far-right expansion. This lack of experience concerns the political party level as well as the public electoral behavior. The post-communist Eastern European countries did not earn the liberal democracy in the way how for instance the French democratic roots were founded. The active political participation still carries negative perceptions since the communist era. The conscious acquisition of the representative democracy and the understanding of democratic values and rights cannot be triggered by introducing institutions or checks and balances. The social and cultural adoption seems to occur at a much slower rate than political adoption. In this aspect the contemporary right-wing populism seems a reasonable reaction. The transition period proved the necessity of reinterpreting the last twenty-five years.