In this thesis, I use the work of Friedrich Nietzsche to offer a detailed account of existential sin. I show that existential sin as a form of self-understanding is deeply embedded in the Christian theological tradition, and that Nietzsche’s account of existential sin should be understood as part of this same tradition. In my reading of On the Genealogy of Morality I show that we need to place sin in close relation to bad conscience, guilt and the genealogical method itself. (...) However, despite being grounded in Christian thought and dependent upon the figure of the Christian God in its origin and emergence, I follow Nietzsche in positing that existential sin continues to exist after the death of God. It is by considering sin as not only a form of self-understanding, but also as a cultural memory, that we can make sense of this claim. For Nietzsche existential sin is at its root a mistaken understanding of human nature that has taken hold of us through Christianity. However, I argue that we need to consider existential sin as a socio-historical answer to the ontological problem of meaningless suffering. Existential sin responds to a fundamental experience of the human condition. With this in mind, in the final chapter of the thesis I examine possible avenues of redemption from post-Christian sin. What options are open to the person suffering from post-Christian sin-consciousness if she cannot turn to religious narratives? I argue that Nietzsche’s redemptive method of genealogy is not sufficient, and that life-affirmation is too demanding. However, a weaker version of life-affirmation in which meaningless suffering is affirmed as necessary, but not desired, does provide a promising alternative answer to the problem of meaningless suffering. (shrink)