Many contemporary bioethicists claim that the possession of certain psychological properties is sufficient for having full moral status. I will call this thepsychological approach to full moral status. In this paper, I argue that there is a significant tension between the psychological approach and a widely held model of Dissociative Identity Disorder (DID, formerly Multiple Personality Disorder). According to this model, the individual personalities or alters that belong to someone with DID possess those properties that proponents of the psychological approach (...) claim suffice for full moral status. If this account of DID is true, then the psychological approach to full moral status seems to entail that the two standard therapies for treating DID might, on occasion, be seriously immoral, for they may well involve the (involuntary) elimination of an entity with full moral status. This result should give proponents of the psychological approach pause, for most people find the claim that current treatments of DID are ethically suspect highly counter-intuitive. (shrink)