This article examines the tabula rasa and structured view of postcom- munism through the institutionalization of electoral and party systems in East Europe and the former Soviet Union. It focuses on changes in elec- toral regulations, electoral volatility, and the effective number of elector- al parties. Most transformations of election rules took place during the foundation of democratic politics and were then consolidated. Only minor reforms have been enacted after initial system engineering. In compari- son with party systems in earlier periods of democratization in western and southern Europe and Latin America, volatility rates and the effec- tive number of electoral parties are among the highest in the world. The postcommunist transitions have institutionalized electoral codes but not party systems.