This article addresses the problem of filling in a missing component of David Miller's non-cosmopolitan theory of global justice, as elaborated in his recent National responsibility and global justice (Oxford: Oxford University Press, 2007). Miller originally included non-exploitation as one of the norms of global justice, but he does not provide a theory of exploitation in his recent book. This article is a preliminary attempt to suggest how Miller might fill in this gap. This article identifies the problems Miller faces in coming up with a theory of exploitation, given the limits imposed by the other parts of his theory of global justice. It examines and criticises several possible theories of exploitation that Miller might use. Finally, it argues that a modified version of Hillel Steiner's liberal theory of exploitation fits into Miller's overall theory of global justice.