A fatality resulting from the suicidal ingestion of risperidone is described. The decedent had a lengthy history of mental illness but was otherwise healthy. Biological fluid samples obtained at autopsy were analyzed for risperidone by high-performance liquid chromatography. The blood concentration of risperidone was 1.8 mg/L, the urine concentration was 14.4 mg/L, and the concentration in the gastric contents was 34.6 mg/L (1.04 mg total). The 9-hydroxy-risperidone metabolite was not detected in the blood or gastric contents; however, the urine contained 17.8 mg/L of this metabolite.