This paper examines the question of whether antisocial personality disorder (APD) can be considered a viable substance abuse typology. The data for APD substance abusers are first reviewed with respect to six properties that apply to establishing the validity of a clinical typology. This is followed by a brief description of the historical context and development of current conceptualizations of antisocial personality. Some possible sources of diagnostic unreliability and instability that could serve to limit the validity of the APD diagnosis are then discussed. Finally, evidence indicating considerable psychiatric heterogeneity within APD substance abusers is described. The findings indicate that although APD substance abusers satisfy many of the criteria for a clinical subtype, the fit is sufficiently imprecise to suggest the need for further refinement. We attempt to point out some of the critical questions, issues, and lines of research that could help to guide future efforts to clarify, refine, and revise the APD formulation, particularly as it applies to substance abusers.