A sample of 441 African American men who were either inpatient heroin or cocaine addicts, or both; were assessed with the MCMI-III. The modal codetype showed primary elevations on the Antisocial Personality Disorder Scale (6A), consistent with previous research using the MCMI-I and MCMI-II with substance abusers. The data were subjected to 3 independent clustering procedures that resulted in general consistency among procedures. The solutions were validated on a randomly selected half of the sample. Three subtypes were variants of the antisocial parent codetype, whereas another subtype was characterized by a Within Normal Limits profile suggesting no personality disorder. These 4 subtypes were also associated with different external correlates with significant clinical import. The results suggest that findings from previous research with substance-abusing patients, using the MCMI-I and MCMI-II, should be applicable to the MCMI-III as well.