Symptoms of antisocial personality disorder (ASPD) and of psychiatric conditions reported to be related to ASPD were subjected to grade of membership analysis, a relatively new procedure for medical classification, to identify the pure types that would empirically emerge in the absence of prior assumptions about the clustering of those symptoms. The sample consists of 914 respondents who participated in the NIMH Epidemiologic Catchment Area Program at the North Carolina site. Symptom and diagnostic data were obtained using the Diagnostic Interview Schedule. Seven pure types emerged from the grade of membership analysis. Two pure types closely resemble the DSM-III portrait of ASPD. Two other pure types consisted of alcohol abuse/dependence symptoms and indicators of illicit drug use for recreational purposes. Only two of the symptomatic pure types were common among women. The first of these was characterized by marital instability, other domestic problems, and employment difficulties; as such this type resembles the DSM-III description of borderline and/or histrionic personality disorder. The other female pure type was characterized by multiple symptoms of depression and selected symptoms of other axis I disorders. The final pure type was characterized by an absence of psychiatric symptoms and served as a comparison group against which the symptomatic pure types were compared.