The authors report about 40 cases of Behçet's disease with vascular involvement, i.e. 32% of a 125 case series. The results were marked by the high frequency of venous involvement (36 cases, including 28 thrombophlebitis of the deep trunks of the lower limbs) and the rarity of arterial involvement (6 cases). Arterial and venous involvements were associated in only 2 cases. Inferior vena caval thrombosis was recognized in 4 cases, including 3 with associated lower limb thrombosis. Superior vena caval thrombosis is found in 6 cases. Superior cavography has allowed demonstrating thrombosis and assessing its extent, to the innominate veins in all cases, to the subclavian veins in 3 cases, and to the axillary veins in 1 case. Cases of arterial involvement include 5 cases of pulmonary arterial aneurysm and 1 of upper limb arteritis affecting the humeral and cubital arteries. It has been revealed by hemoptysis in all cases. Angiography has allowed establishing the diagnosis of aneurysm in 4 cases (3 with partial thrombosis and 1 without thrombosis). CT revealed the diagnosis of completely thrombosed aneurysms not opacified by angiography in another case.