Triage of forensic patients is a concern with growing interest. The present study focuses on the tri-age of mentally disordered offenders in belgium. Psychiatric prevalences and lengths of stay of high and medium risk facilities reported in publications and reports were analysed. It appears that foren-sic patients are triaged according to their diagnostic and risk profile. Lengths of stay increase with the risk level of institutions. Higher comorbidity and personality disorder rates were found in high risk settings, more primary diagnoses of psychotic disorders were found in medium risk facilities. Mental retardation and substance abuse were found to be transnosographic and were found in every risk level.