This article considers one seemingly compelling justification for immigration restrictions: that they help restrict the brain drain of skilled workers from poor states. For some poor states, brain drain is a severe problem, sapping their ability to provide basic services. Yet this article finds that justifying immigration restrictions on brain drain grounds is far from straightforward. For restrictions to be justified, a series of demanding conditions must be fulfilled. Brain drain does provide a successful argument for some immigration restrictions, but it is an argument that fails to justify restrictions beyond a small minority of cases.