Behçet's disease is a chronic multi-systemic disease of unknown origin that includes mucocutaneous, ocular, cardiac, vascular, renal, gastrointestinal, neurologic and cutaneous involvement. The disease is spread throughout the world, but it is most prevalent in the eastern Mediterranean region-along the Silk Road-, and in Japan, China, and Korea. Recently, we treated a Mongolian patient who had complete-type Behçet's disease. As far as we know, this case is the first report of a Mongolian with Behçet's disease in the English literature. HLA typing in this patient revealed A2, A24; B51, B35; Cw4, Cw7; DR9, DR11. Study of the MICA genetype showed *5, *6 positive. Our data provided adequate evidence, from an epidemiological aspect, to support the belief that Behçet's disease is most prevalent along the old Silk Road.