This article focuses on the mediation of Catholic Church in the Beagle Channel dispute between Chile and Argentina between 1979-1984. The thesis of this paper is that theorical approach compatible with the role of the Catholic Church in the Beagle conflict is the idealistic vision of Theory of International Relations. Therefore, this work is organized along two lines: 1) Underline the main thesis of the idealist paradigm in International Relations and the Social Doctrine of the Church, emphasizing the connection of meaning between them. 2) Since the thesis will focus on the specific problems of the Papal role in the conflict.