A pressing and difficult practical problem concerns the general issue of the right social response to offenders classified as having antisocial personality disorder. This paper approaches this general problem by focusing, from a philosophical perspective, on the still relevant but more approachable question whether psychopathic offenders are morally responsible. In particular, I investigate whether psychopaths possess moral understanding. A plausible way to approach the last question requires a satisfactory philosophical interpretation of the empirical evidence that appears to show that psychopaths (...) fail to draw the distinction between conventional and moral norms. Specifically, I will consider a recent philosophical debate polarized between supporters of rationalist and sentimentalist accounts of moral understanding. These opponents have discussed whether the case of psychopathy offers empirical support for their account and undermine the rival view. I will argue that the available empirical data leave the outcome of this discussion indeterminate. However, this implies that both these principal theories of moral understanding, if independently motivated, would imply that psychopaths have certain deficits that might affect their moral understanding and, consequently, their moral responsibility. (shrink)