Despite the prevalence of "Logos" as a christological title in his works, Irenaeus of Lyons has not been considered a Logos theologian due to an untenable presupposition that the Greek doctrine of the Logos has no place in the biblical thought of Irenaeus. The purpose of this article is to study Irenaeus' use of "Logos" in explaining the nature and work of the Second Person, particularly in his pre-incarnational state. Furthermore, I read Irenaeus in conjunction with Justin's Logos theology to demonstrate that Irenaeus alters the dominant understanding of Logos theology in the second century. In Irenaeus' works, the title "Logos" functions to unite the Father and Son in one, equal divine nature, allowing the Son to work on behalf of the Father in creation as an agent of creation and revelation. Despite the prevalence of "Logos" as a christological title in his works, Irenaeus of Lyons has not been considered a Logos theologian due to an untenable presupposition that the Greek doctrine of the Logos has no place in the biblical thought of Irenaeus. The purpose of this article is to study Irenaeus' use of "Logos" in explaining the nature and work of the Second Person, particularly in his pre-incarnational state. Furthermore, I read Irenaeus in conjunction with Justin's Logos theology to demonstrate that Irenaeus alters the dominant understanding of Logos theology in the second century. In Irenaeus' works, the title "Logos" functions to unite the Father and Son in one, equal divine nature, allowing the Son to work on behalf of the Father in creation as an agent of creation and revelation.