In the common opinion it is considered that the most important representatives of existentialism are atheist or agnostic philosophers such as Friedrich Nietzsche, Martin Heidegger, Jean-Paul Sartre or Albert Camus. However, this current developed on the basis of Christian teaching, starting in late Antiquity with The Blessed Augustine of Hippo, then continuing in modernity with Blaise Pascal, to finally find its explanation in the thinking of the Danish theologian and philosopher Søren Kierkegaard, the father of existentialism. The contribution of the Christian tradition in the formation of this philosophical current should not be omitted or denied. To interpret man in an existential way is first of all a merit of the Christian teaching, through the importance it gives to the uniqueness and absolute value of each human being. Considering these aspects, the main objective of this article is to identify and analyze the origins of this philosophical current, and at the same time to prove that the existentialism promoted by the philosophers mentioned at the beginning is only a secularized version of Christian existentialism.