The findings of this study revealed that a small group of patients, about 10 percent, in a forensic psychiatric hospital were responsible for more than 60 percent of all violent episodes recorded during a 1-year study period. The aggression and violence of this 10 percent subgroup of patients was frequent, diversified, and serious. In recent years, the perpetration of violence by psychiatric patients during inpatient treatment has received considerable attention. A consistent observation which has emerged from empirical investigations is the presence of a very small subgroup of patients responsible for the majority of violent episodes in psychiatric settings. This study contributes to this emerging research by looking at the prevalence of chronically violent patients (CVPs), the nature of their violence, and the associated static historical and clinical risk factors. The study was based on a 1-year follow-up investigation of all violent episodes committed by a sample of 527 patients in a forensic psychiatric hospital in British Columbia, Canada. Tables, figure, notes, and references