Behçet's disease is a multisystemic disorder characterized by recurrent ulcers of the mouth and genitalia and relapsing iritis. Four types of vascular lesion are recognized in Behçet's disease: arterial occlusions, aneurysms, venous occlusions, and variceal development. The incidence of vascular involvement reported in the literature ranges from 7% to 29%. The aim of this study was to determine the rate of vascular involvement in Behçet's disease at our hospital between 1983 and 1992. Of 1200 patients with Behçet's disease, 173 (14.4%) had venous manifestations and 19 (1.6%) had arterial manifestations (in some patients more than one organ was involved). In the group of patients with venous manifestations, there were 154 (12.8%) with venous thrombosis, 17 (1.4%) with vena cava superior syndrome, 5 (0.4%) with inferior vena cava syndrome, 5 (0.4%) with varices, 2 with upper extremity venous thrombosis, 1 with internal jugular vein thrombosis, 1 with cavernous sinus thrombosis, and 1 with hepatic vein thrombosis. In the arterial manifestation group there were 7 femoral, 3 abdominal, 3 popliteal, 2 iliac, 2 pulmonary, 1 axillary, and 1 carotid artery aneurysm as well as 3 arterial occlusions. We concluded that vascular surgeons dealing with young adults should bear Behçet's disease, an uncommon clinical entity, in mind.