It has been suggested that certain tissue types are associated with different clinical manifestations of Behçet's disease in Japan and England. Regional differences in the associations between HLA antigens and Behçet's disease have been established. We tissue type 119 patients with Behçet's disease in Istanbul and attempted to correlate various clinical manifestations with HLA antigens. The frequency of only one tissue antigen, HLA-B5, was found to be increased in these series. HLA-B5 was present in 94 of 119 patients (77%) compared to 89 of 268 controls (33%), P less than 0.0001, ARR = 6.79. Age of onset, sex, incidences of ocular disease, arthritis, thrombophlebitis and erythema nodosum did not show any positive or negative associations with any of the alleles tested.