DBT, developed by Linehan (1993), stems from the belief that patients lack skills in mindfulness, interpersonal regulation, emotion regulation, and distress tolerance; further, personal and environmental factors inhibit the use of adaptive skills and reinforce maladaptive skills. DBT combines weekly group skills training with individual behavioral psychotherapy in which the patient's presenting behavior sets the agenda. Treatment is structured and hierarchical, such that treatment targets the most problematic behavior. Overall, DBT blends validation and acceptance strategies with change-focused cognitive behavioral therapy. In the current study, 8 male forensic patients in a high security hospital who met the criteria for borderline personality disorder underwent 18 months of DBT. They completed three psychometric tests at pretreatment, midtreatment, and posttreatment, and also at a 6-month follow-up. A comparison group of nine patients, determined to have similar personality disorder, received the usual treatment available in the hospital but excluding DBT. The comparison group completed the same tests at the same time intervals. For both groups, all instances of behaviors related to anger and violence were monitored for three 6-month periods prior to, during, and after treatment. The evaluation found that overall, patients in the DBT group made greater gains than patients in the comparison group regarding reduction in the seriousness of violence-related incidents and in self-report measures of hostility, cognitive anger, disposition to anger, outward expression of anger, and anger experience. These findings suggest that compared to standard hospital treatment, DBT is more effective in reducing the seriousness of violence-related incidents and self-reported anger and hostility in male forensic patients. 4 tables and 55 references