In order to assess risk factors for suicide among patients with schizophrenia, we compared 32 patients with schizophrenia who committed suicide during an 11 year follow-up with a control group of 64 schizophrenics who did not commit suicide. A history of previous suicide attempts was the factor most strongly related to suicide. In females we found an increased risk for suicide among unmarried, divorced or widowed and among those living alone. In males we found an increased risk among those with a history of alcohol abuse. In contrast to findings in other studies, distribution of age and sex and a history of depressive episodes were factors not associated with an increased risk for suicide. We conclude that suicidal acts among schizophrenics are often impulsive and difficult to predict. Traditional risk scales are of limited value in the clinical assessment of suicidal risk.