The analysis of the success of the transition from a planned to a marketoriented economy. Former communist countries, members of the former Eastern Bloc with the addition of Yugoslavia, which are now full members of the European Union, were taken into consideration. The first part of the paper slowly introduces the topic, presents the characteristics of communism and briefly discusses the main features of that period and at the end of the chapter explain the reasons why the communism was destroyed. The next chapter briefly describes the life of each of the analyzed countries during the communist rule and chronologically traces their path from the very beginnings to the final collapse of communism. The third part of the paper analyzes the sensitive period between the collapse of communism and the beginning of transition in Eastern Europe, describes the beginning of the transition period that brought great social and economic changes and the very high expectations of this period. A key part of the paper provides an analysis of performance and adjustment to the transition process of all analyzed countries. It describes in details the transition period in each of these countries, analyzes the approach to the transition and the reforms implemented in that period before accession to the European Union. Official statistics of each of the countries taken into consideration are presented and finally the success of the transformation of the economy of each country is analyzed separately. The last part of the paper especially emphasizes the period of transition in the Republic of Croatia. It describes the chronologically turbulent period of transition accompanied by the events of the war, explain various reforms and models of the privatization and finally present the results of the transition period and a comparison with the previously analyzed countries. At the end of the paper, the final opinion is the conclusion of the author of this final work.