A 32-year-old male suffering from thrombophlebitis of the right leg was admitted to our hospital because of massive hemoptysis. Chest radiography showed multiple rounded opacities in the right lung field. Pulmonary angiography revealed multiple aneurysms of the right pulmonary arteries and thromboembolism of the left pulmonary artery. Venography demonstrated obstruction of the deep veins of the right leg and the right femoral vein, and deep vein thrombosis was diagnosed. A more precise diagnosis was Hughes-Stovin syndrome, that is, venous thrombosis especially of the vena cava, accompanied by single or multiple pulmonary arterial aneurysms in young patients. Furthermore, the patient had an aphthous ulcer in the oral cavity, an ulcer in the genital region, leading to a diagnosis of the incomplete type of Behç et's disease. Chest radiographs 3 months after the initiation of corticosteroid showed complete resolution of the aneurysms. Repeated pulmonary angiography also showed partial recanalization of the occluded arteries. This report describes this very rare case of Behç et's disease presenting with Hughes-Stovin syndrome.