The article examines the changes that have taken place in Poland’s informal institutions during the country’s political and economic transition from 1989 to 2009, as compared with other countries in Central and Eastern Europe. The author also sets out to determine to what extent the informal components of the institutional system laid the groundwork for formal institutions and whether changes in informal institutions were aimed in the right direction—whether they supplemented and reinforced the work of formal institutions. The comparative analysis of the informal components of the institutional system was based on a study of value systems, using research findings obtained by Ronald Inglehart and Christian Welzel as well as data from the World Values Survey. The author concludes that: a) the changes introduced in Poland’s formal institutions during the country’s political and economic transition after the fall of communism have been incompatible with the development of the informal components of the institutional system; b) Poland’s informal institutions have undergone an evolution leading to a change in value systems in a direction consistent with the processes observed in highly developed countries; c) the most far-reaching changes involved an increase in self-expression values accompanied by a weakening of conservative values; d) there was also a slight increase in indicators reflecting rational values. The level of rationalism in Poland is lower than in other transition economies such as the Czech Republic, Slovakia and Hungary. At the same time, traditional values hold strong in Poland, which, according to the author, is one of the signs of maladjustment between the informal and formal components of the institutional system (and consequently an institutional imbalance).