The RSUs aim to provide assessment and treatment of mentally disordered offenders in conditions of medium security. They are staffed exclusively by health professionals, and all units are multidisciplinary, comprising a psychologist, psychiatrist, occupational therapist, social worker, and psychiatric nurse. The RSUs have an important assessment role to play in homicide cases. RSUs also accept mentally abnormal killers from Special Hospitals in order to assess their suitability for discharge into the community. Although there is no centralized data base of offenders admitted to RSUs after homicides, it appears that most are diagnosed with schizophrenia or major depressive illnesses. Offenders diagnosed with psychopathic disorders are more often referred to Special Hospitals. Most offenders housed in RSUs killed either a family member or friend. A case history illustrates the assessment and treatment procedures followed in an RSU. 1 table and 32 references