It is already known that the famous phrase of Athanasius of Alexandria: God became man so that we might become god (De Inc. 54,3) comes from the theology of Irenaeus of Lyon (Adv. Haer. III,19,1). In fact, the whole maturity period of the Alexandrian bishop is placed under the sign of a visible irenaean influence. In this study we intend to analyze the differences and, especially, the similarities that exist between the two Fathers regarding the entire process of human salvation. Several ideas used by Athanasius, such as the corruptibility of the human being, that comes from nothing, the need of man to be restored by God, the deification of man through the Word' incarnation, or that the immortality and incorruptibility acquired by the death and resurrection of Christ, are all inherited theories of Irenaeus of Lyon. For example, the Pauline concept of recapitulation (Eph. 1, 10), so dear to Irenaeus, that Christ summarizes in him all humankind and its history by offering briefly salvation (Adv. Haer. III, 18, 1; III, 22.1), was partially adopted by Athanasius which simplifies it, speaking only about the kinship and the incorporation of all in Christ. However, Irenaeus' theory of restoration in Christ (Adv. Haer. V,14,2; V,21,1) is much more developed and enriched by the author, who will perceive the salvation not simply as a return of man to its original state, but as something more, which will allow him to develop his doctrine of deification in Christ.