Behçet's disease is a systemic vasculitis generally involving the venous system. Arterial manifestations, usually aneurysm or more rarely occlusion, are less common. We analysed 5 cases of Behçet's disease with arterial aneurysm complications. There were 4 men and 1 woman, mean age 34.6 years. Mean delay to arterial complications was 7.8 years after the first sign of the disease. Four patients showed evidence aneurysms of the pulmonary arteries. One patient developed an aneurysm of the aortic and iliac artery. Phlebitis was associated with arterial involvement in 4 patients. Combined corticosteroid and cyclophosphamide therapy enabled regression of pulmonary aneurysms in 2 patients. One patient was operated, outcome was favorable. Histology showed fragmentation of the media associated with vasculitis. Two patients with pulmonary aneurysms died of massive hemoptysis.