This essay takes up a challenge recently posed by Graham Oppy: to clearly express, in premise-conclusion form, Hegel's version of the ontological argument. In addition to employing this format, it seeks to supplement existing treatments by locating a core component of Hegel's argument in a slightly different place than is common. Whereas some prominent recent treatments (Williams, Bubbio, Melechar) focus on Hegel's definition of the Absolute as the Concept, from the third part of his Science of Logic (the Doctrine of the Concept), mine focuses on earlier definitions from the first (the Doctrine of Being). As I hope to show, there are even more resources in Hegel's Logic for an ontological argument than those emphasized in recent treatments: the concept, the Idea, etc. Already in the first third of the Logic, we find a compelling response to a famous Kantian counter-argument to the ontological proof. The counter-argument is summed up in the phrase ‘existence [Sein] is not a real predicate’. Hence, Hegel's response as I interpret it will take the form of a competing analysis of Being, a Lehre vom Sein (Doctrine of Being). What do we learn when we put the ontology back into Hegel's ontological argument? That Being is neither predicate, nor subject, nor copula, but a monist (or ‘infinite’) category. The larger importance of this exercise to our understanding of Hegel's thought lies in the way it clarifies his profound debt to even non-idealist conceptions of God, such as the one espoused by Spinoza.