Abstract: Behcet’s Disease (BD) is a multisystemic disease with a peculiar distribution in the world. The disease is specially seen in the countries bordering the ancient SILK ROAD specially Japan, China, Korea, Iran, and Turkey. The majority of reports on BD are on hospital based patients. Others are either local based patients or epidemilogical studies on a small area. The only two nationwide analysis of BD is from Japan and Iran. The major methodological difference between the 2 surveys is that in Iran all patients were examined and analyzed on a predefined protocol by the same group of physicians. The comparison of results between these 2 surveys is interesting because the 2 populations are racially different, although they share some genetic background via the invasion of Iran by Turks in the 12th Century. The annual incidence fluctuates between 250 and 350 new patients for a population of 60 millions, which may correspond to a prevalence of 1 BD for 6000 inhabitants. The disease distribution changes widely from one region to another, much like in Japan. The disease is twice as frequent in Turk ethnic group than in Caucasians. The sex distribution is 54% males and 46% females. The mean age at the onset of the disease is 26 (confidence interval at 95% = 0.3) with a standard deviation of 9.7. Mucous membrane manifestations were present in 97% of patients (oral aphthosis in 97 and genital aphthosis in 65%). Skin manifestations were present in 71% of patients (pseudofolliculitis in 62%, erythema nodosum in 22%, and other skin lesions specially skin aphthous lesions in 6%). Ocular manifestations, the major morbidity cause of the disease, was present in 56% of patients (anterior uveitis in 41%, posterior uveitis in 45%, and retinal vasculitis in 31%). Joint manifestations were present in 35% of patients (arthralgia in 15%, mono-arthritis in 8%, oligoarthritis in 17%, and ankylosing spondylitis in 1.5%). Neurological manifestations were rare, seen in only 3.3% of cases (central manifestations: 3.1%, peripheral manifestations: 0.2%). Cephalea is seen in 10% of cases but most of them are tension headaches. Gastro-intestinal manifestations were also rare, seen in 7.9% of cases (acute abdomen 1.7%, proctorrhagia 0.8%, chronic recurrent diarrhea 2.1%). Peptic ulcer was seen in 1.6% and gastric upset in 2.9% of cases. Orchiepididymitis was present in 5.7% of cases. Phlebitis was seen in 6.2% of cases, large veine thrombosis in 1%, arterial thrombosis in 4 cases, and aneurism in 25 cases. Pulmonary and cardiac manifestations were extremely rare (0.8% and 0.5%). Abnormal urine sediments were seen in 10% of patients. In 14 patients renal biopsy was necessary for chronic proteinuria (WHO type 2: 3 case, type 3: 5 cases, type 4: 5 cases, amyloidosis: 2 case). Pathergy test was positive in 58%, HLA-B5 in 54% (34% in normal population), HLA-B27 in 9.4% (4% in normal population), false positive VDRL in in 1.6% of patients.