We surveyed the 10-yr mortality among 152 Behçet's syndrome (BS) patients who had registered at a BS out-patient clinic and compared it to the expected mortality in the general population. Information on mortality was available in 79% of the study group, among whom six patients (all males) had died. The observed mortality of two patients in the 15-24 yr age bracket was significantly above that expected in the general population. BS is a cause of increased mortality in the young male patients