There is wide variability in the juvenile offender population, requiring different approaches to treatment and rehabilitation. Behavioral typologies that have emerged in research of samples of male juvenile offenders have aided clinicians in assigning appropriate treatment. The current study utilized the BASC Self-Report of Personality Adolescent Form (BASC-SRP-A) to observe the various behavioral and personality typologies that emerged from a sample of 103 male adolescent detainees, aged 12 to 17 years, at a short-term regional youth detention center. Secondly, these cluster-derived typologies were cross-validated using scales from the MACI and using youth offense history. Participants completed both the 186-item BASC-SRP-A, which measures aspects of youth’s behavior, and the 165-item MACI. Results of hierarchical cluster analysis on the BASC-SRP-A responses indicated five clusters or typologies among the sample of male adolescent offenders, only one of which suggested severe problem behaviors. When compared to the results from the MACI scales, all but one of the BASC-SRP-A clusters scored in the at-risk or clinical range on the MACI scales. Thus, the MACI highlighted problem behavior where the BASC-SRP-A did not, perhaps due to the fact that the MACI was normed on a clinical population, while the BASC-SRP-A is used primarily in educational settings less sensitive to clinical symptoms. The findings underscore the importance of using multiple forms of assessment when determining a comprehensive treatment plan. Tables, figures, references, notes