We conducted a field survey to establish the prevalence of Behçet's syndrome among all the inhabitants aged 10 years or older in a village in northern Turkey. The prevalence of Behçet's syndrome was 19/5,131. There were 13 females and 6 males. None had eye involvement. Pathergy test was positive in 6/18 (33%) and 5/19 carried HLA-B5 (26%), suggesting that the previously established association of HLA-B5 in Behçet's syndrome is mainly true for hospital based populations. Moreover, the pathergy test was less commonly positive in milder disease.