Although the problem of aggression generates considerable social concern, aggressive delinquents are rarely provided with more than minimal treatment following legal processing and incarceration. When treatment is available, it usually consists of some form of ineffective or even counterproductive punishment administered in the context of a token economy. An alternative approach is termed stress inoculation in which clients are educated about anger and aggression, trained in coping skills, and then practice applying these skills in simulated provocative situations. In this study, institutionalized males between 13 and 18 years old who had a history of aggressive behavior were perceived by the correctional staff as having significant anger control problems were exposed to 3 experimental conditions: 9 received no treatment, 10 participated in a stress inoculation regime, and 8 were involved in relaxation training and rehearsed practice of nonaggressive responses to provocations. All subjects were assessed 2 weeks before and after the experimental treatment period using an anger inventory, the Imaginal Provocation Test, the Role Play Provocation Test, the Irrational Beliefs Test, institutional behavior ratings, and an Experimental Demand Assessment. Subjects were seen in hourly sessions, twice a week over a 5-week period. Specific treatment procedures used in stress inoculation are detailed. The first 2 sessions discussed the causes of anger, and a coping strategy was presented in the third session. The following 2 meetings explored coping skills in depth, while the remainder of the treatment focused on role playing provocation incidents to practice coping skills. Although both treatment conditions reduced degrees of self - reported angry feelings and the level of self - reported verbal aggression following imaginal provocation, only stress inoculation was effective in decreasing the actual level of verbal aggression exhibited in role playing provocations involving another person. Subsequent research could develop institutional programs that use the procedures demonstrated in the individualized stress inoculation therapy. Tables and 31 references are included. (Author abstract modified)