In the past, the UN dealt with the problems of mentally ill offenders through specific provisions contained in the Standard Minimum Rules for the Treatment of Prisoners. In 1986, the UN issued a report on protecting the rights of the mentally ill, preventing psychiatric abuses, and improving institutional mental health and medical practices. The current UNICRI project was divided into three stages: (1) review country experiences in managing mentally ill offenders; (2) study actual features of systems and programs for mentally ill offenders; and (3) provide guidelines for managing mentally ill offenders. The project focused on such issues as social and judicial management of mentally ill offenders, imputability, dangerousness, and treatment. Comparative law and the results of field studies in Canada, Egypt, England, Wales, Germany, Italy, Japan, Nigeria, Peru, Sweden, and Thailand are reviewed that deal with mentally ill offenders. The review looks at criminal responsibility, diminished responsibility, the treatment of nonresponsible offenders, the treatment of borderline cases, the use of psychiatric and psychological examinations to diagnose responsibility, specific mental disorders, criteria for determining dangerousness, sanctions, the role of psychiatry in the criminal justice system, and correctional reform. References, notes, tables, and figures