Augustine's understanding of the church as part of the totus Christus – the ‘whole Christ’ – has become an important resource in contemporary theology, offering a robust vision of the church's union with God. Yet a key critique maintains that it threatens to elide the distinction between the perfected Christ and the created church. This article addresses this issue by asking how the totus Christus doctrine relates to the doctrine of participation. For Augustine, participation is a metaphysical category that expresses the creature's dependent, non-divine status, its essential being out of nothing. The totus Christus doctrine is most explicitly an exegetical, not metaphysical doctrine. Nevertheless, by putting these two facets of Augustine's thought together, we can see the way in which they mutually reinforce the view that the astonishing claims of unity in the totus Christus are structured by a larger theological grammar that distinguishes God and creature.