Aggressive and intensive case management and a comprehensive array of community support services are the keys to reducing the risk of violence by people with serious mental illness in the community. The authors describe the elements of intensive case management for potentially violent clients, including use of individual case managers responsible for small caseloads, 24-hour availability of case managers, and strong linkages to agencies providing mental health services, substance abuse treatment, and social services as well as to the criminal justice system. They summarize the results of three recent studies of intensive case management programs suggesting that this intervention is effective in reducing clients' dangerousness in the community. They discuss cultural and human resource issues that affect planning of intensive case management services. Intensive case managers need to be "boundary spanners" with the training, experience, and personality to bridge the often-broad gap between human service and criminal justice systems.