The collapse of the communist regimes in Europe at the turn of 1980's/1990's led made it necessary to seek new models of State and Churches relations in the post-Communist countries. However, even though two decades, 1990-2010, have not been enough to bring the process of transformation to completion, we can state that, at that time, the basic regulative principles of the relations in the politico-religious area have been specified and legally laid down. The study Concordat Agreements between the Holy See and the Post-Communist Countries (1990-2010) endeavours to describe and evaluate in a systematic manner a relatively extensive area of contractual regulation of relations between the Catholic Church and the post-Communist countries on the basis of research of concordat agreements. On the basis of comparative evaluation, it shows the prevailing models of solutions as well as their inner adequacy to the religious phenomenon and to the pluralistic democratic social order.