This study concerns 11 patients; 7 had a Rendu-Osler-Weber disease. They were 5 males and 6 females, including 3 children. In addition to the thoracic symptoms of cyanosis, clubbing and polycythemia, 4 had been treated for a cerebral abscess. Standard chest films were normal in 2 cases. The anatomy of the malformations was studied by CT scans and angiographies. The 11 patients had 25 malformations, bilateral in 5 cases. All were hypoxennic. Four solitary lesions were resected by 3 lobectomies and 1 excision. Seven multiple lesions were treated by 1 pneumonectomy, 1 lobectomy, 1 segmentectomy + 1 excision and by 1 excision. In 2 of these cases radiology and surgery were associated. Two patients were treated by radiological vaso-occlusion. The 9 operated patients have remained cured with a mean 4.7 year follow-up, one still has a small, non evolutive anomaly. The 2 radiologically treated patients still have 2 non evolutive lesions. This cases allow a discussion concerning the diagnosis and treatment of arteriovenous malformations of the lung which can provoke grave complications. A long follow-up of treated patients is necessary.