Considering the title of this thesis, The Ethical-Moral Fundamentals of Peace on De Civitate Dei of Saint Augustine, we debate the Augustinian view of peace and its influence in the Church Magisterium, specially in the Pacem in Terris, Gaudium et Spes and Sollicitudo Rei Sociali documents. According to these documents the social order is indispensable to the realization of peace. Nevertheless, without despising this aspect, saint Augustine affirms that this order presupposes the peace of the individual, which arises from the balance between the uti and the frui, both the basic principles of ethics and moral. Saint Augustine s peace can also be analysed according to the moral theology, because the peace to be reached needs the valorization of both the subjectivity and the intersubjectivity. It is true that the means indorsed by saint Augustine to achieve peace are still pertinent, because he had already perceived by intuition that the peace is only effective when it involves all the aspects related to the human being and his social context, without confusing it with intimism or with a spirituality not incarnated within the social structures. Therefore, tranquilitas ordinis does not mean both the conformism or the resignation with the unjust and inhuman structures of this world. Because everybody who lives according to the order established by God knows perfectly that must cooperate, on the Earth, to have justice and peace, without loosing the sight of the Celestial Jerusalem, which is the aim of everyone that are commited, without discouragement, to establish the seeds of the Kingdom of God in this exile. This research plans to contribute to the restoration of the whole vision of the human being and to redeem the many dimensions of peace.