The present dissertation has the title Evangelism as Contextual-Liberating Action, a Theological Pastoral Study of the Theology of Orlando Costas. It has the goal to locate a proposition of the Theology of Contextual Evangelism of the mentioned author with an appropriate epistemological horizon in order to reconsider a pastoral theology, and more specifically the evangelistic character of the Church in the present days. This is done mainly by the fact that Costas develops a theological method with contextual and historical broadness which has its key in a theology which is eminently dialogical. As the present days are configured not only as a new locus for living the Christian faith, but also as the proclamation of the good news of the kingdom, this research emphasizes the need to develop a (re)new(ed) reading about the mission of the Church, in the light of the kingdom of God. Inspired by the trinitarian dynamic, Christians can find creative possibilities to respond to the divine summons to love-in-service, understanding that Christian Mission is a continuity, in the strength of the Spirit, of the liberating mission which flows from the heart of God, his overflowing love for his creation. In this sense, this dissertation offers a contribution to recover an evangelistic service which realizes itself as overflowing God’s love in the human context, inviting men and women to an experience of faith which is articulated not as a dogma, religious adhesion or a simple experience of ecstasy, but as a specific orientation of their existence, which challenges human freedom to make an option for the Trinitarian God as the source of life.