The risk of suicide among the first-degree relatives of 195 schizophrenic and 315 manic-depressive patients in a long-term study was estimated. The findings demonstrate a higher risk of suicide among relatives of psychiatric patients in comparison with relatives of surgical controls. Male relatives had a higher risk of suicide than female relatives. When suicide risk in the relatives was analyzed according to the presence or absence of suicides in the patients, relatives of patients who had committed suicide showed significantly higher risk of suicide than the remaining relatives. These results should be considered by clinicians when assessing suicide risk in patients and their relatives.