This research paper examines the Concordat concluded with Poland in 1993 in the broader context of the treaty-making practice of the Holy See. The main question which it seeks to answer is the issue of similarities and differences between the Polish Concordat and other agreements the Holy See concludes to stabilize the legal framework within which the Catholic Church operates in different countries all over the world. The analysis demonstrates how the solutions adopted in the Polish Concordat have influenced the later practice of the papal diplomacy concerning the Concordats and treaties having a Concordat-like character. The main conclusion underlines the particular importance of the references to human rights concepts contained in the Polish Concordat, and demonstrates how it influenced the later treaty-making practice of the Holy See. It submits the hypothesis that by invoking human rights (especially freedom of religion) in many agreements to which it is a party, the papal diplomacy seeks to bridge the ideological gap between the needs of Church for legal stability and domestic order of those states whose political regime is founded upon the principle of secularism/laity.