Behçet's disease is recognised as a chronic multisystem disorder with vasculitis as its underlying pathological process. Cardiac involvement is rare and often associated with poor prognosis. A large right atrial thrombus, pulmonary aneurysms and aortic pseudoaneurysm that developed 17 years after surgery for bilateral renal artery stenosis is presented in a 26-year-old Behçet's disease patient. He was admitted to the hospital with fever of unknown origin associated with chest pain, dyspnea, cough, haemoptysis and pulmonary opacity in chest X-ray. Initial pulmonary CT demonstrated small subpleural infiltrates bilaterally, one of which was round and suspected as being metastatic. Examination of open lung biopsy demonstrated haemorrhagic infarct surrounded by some occluded pulmonary arteries. Subsequent CT showed pulmonary aneurysms compatible with Behçet's disease. Echocardiography demonstrated a large pedunculated mass in the right atrium. Injection of urographin showed a right atrial mass and a large right pulmonary artery aneurysm. The atrial mass was completely excised during open heart surgery and was identified as being an organising thrombus. Eight weeks later while taking prednisone, he was readmitted because of an infected mid sternal wound. CT showed slight separation of the stemum, retrosternal fluid, pulmonary arteries aneurysm and ascending aorta aneurysm. The next day, the patient died from massive bleeding from his ruptured ascending aortic pseudoaneurysm. Bizarre presentation of arterial and venous thromboses or arterial aneurysm formation, particularly in young patients, should suggest Behçet's disease.