We compared residential addictions treatment clients meeting full criteria for antisocial personality disorder (ASPD+) with those reporting syndromal levels of antisocial behavior only in adulthood (AABS+) on demographics, antisocial symptomatology, drug history, axis I comorbidity and characteristics of index treatment episode. We examined these issues in the sample as a whole, as well as separately in male and female respondents. Among both men and women, ASPD+ initiated their antisocial behavior earlier, met more ASPD criteria and endorsed more violent symptoms, than AABS+. Male ASPD+ also met criteria for more lifetime axis I diagnoses and reported more years of drug involvement than male AABS+. Trends were observed toward poorer retention in treatment among ASPD+ than among AABS+ participants of both genders randomized to a planned duration of 180 days, but retention did not differ between ASPD+ and AABS+ randomized to a planned duration of 90 days. Our findings, which replicate and extend previously published results, carry potential implications for treatment programming and for the nosology of ASPD.