The MMPQ is an abbreviated form of the Minnesota Multiphasic Personality Inventory. The MMPQ has been effective in identifying behavior problems among adult male prisoners on the basis of measured personality characteristics. In order to investigate its reliability in measuring personality characteristics among juvenile offenders, the 192-item MMPQ was administered to 32 subjects in a federally sponsored rehabilitation and vocational training program. Significant relationships between MMPQ scores and the following behavior criterion variables were hypothesized: (1) the time required for inmates to complete the rehabilitation program; (2) inmate escape behavior; (3) inmate assault behavior; (4) other serious behavior problems including drug and weapon possession, destruction of property, and serious violations of institutional rules; and (5) behavior in which inmates become assault victims. Significant statistical correlations were found between MMPQ scores and all behavior criteria except inmate escape behavior. In addition, computations between the behavior criterion variables revealed that all forms of anit-social behavior among the inmates were positively related to longer periods of incarceration, and that inmates committing one type of offense within the institution tended to commit other types of offenses. Finally, the average 'T' scores of the adolescent sample were used to construct a group profile that was compared to the group profile of an adult prison sample. Both groups produced strikingly similar profiles. Data are presented in tabular and graphic form. Related research is reviewed; foonotes and a bibliography of approximately 40 references are included. Appendixes contain additional subject and test data.