Megargee developed a typology based on the hypothesis that extremely aggressive individuals can be divided into two distinct personality types: the overcontrolled and the undercontrolled personalities. The overcontrolled individual is one characterized by an extremely rigid defense system against the expression of aggressive impulses, irrespective of provocation. This psychological process is similar to the so-called pressure-cooker effect. A single or rare aggressive outburst culminates in the death of the victim. The undercontrolled individual has failed to learn how to adequately control aggressive impulses. They typically have a long history of violent, assaultive behavior. The Overcontrolled Hostility Scale (O-H) can identify overcontrolled individuals, but not the undercontrolled individual. In this study, it is assumed that when separated on the basis of aggressive impulse control, two distinct types of adolescent murderers might exist: the overcontrolled and the not overcontrolled. Minnesota Multiphasic Personality Inventory (MMPI) data were collected on 18 adolescent murderers, 18 violent young offenders, and 18 nonviolent youths convicted of property offenses. The MMPI was administered to a comparison group of 18 adolescent nonoffenders. The results of this study were not statistically significant. Results supported the main hypothesis, which states that O-H scores would be higher in an adolescent homicide group than other groups of adolescents that did not commit murder. These findings suggest that the use of the O-H scale might help identify youth at risk for violence and provide important data regarding the potential for serious adolescent violence and later adult violence. Future research should attempt to develop adolescent norms for the overcontrolled hostility scale. 1 table, 32 references