The conceptual, clinical, and empirical overlap between the constructs of narcissistic personality disorder (NPD) and antisocial personality disorder (ASPD) is reviewed and their descriptive discriminability is investigated. Twenty-four patients with NPD and 16 patients with ASPD were compared on 33 characteristics for pathological narcissism assessed with the semistructured Diagnostic Interview for Narcissism. The results confirm a sufficiently broad array of similarities that the question of whether these categories should be kept separate (as they are in DSM-IV) is underscored. The results also indicate important areas of difference. The NPD sample was best discriminated from the ASPD sample by their grandiosity, that is, the tendency to exaggerate their talents, and to regard themselves as more unique and superior.