This article examines elements of determinism and naturalism in Cormac McCarthy's twenty-first-century novels, No Country for Old Men and The Road. While naturalism has been noted in McCarthy's work prior to these novels, this article contends that the character and strength of naturalism has changed in the most recent works. This change is placed in the general context of naturalist theory, as well as what the article argues is a more general resurgence of naturalism in American culture post-9/II. In particular, this article examines the implications in McCarthy's work for the extent to which the deterministic dimension of naturalism prevents us from judging characters morally, since they exercise at best highly limited free will. The article provides a derailed analysis of this phenomenon in the two novels, and also uses this to place them in the wider American and global twenty-first-century context.