Arteriovenous fistula (AVF) is rare congenital pathology of the bronchopulmonary system vessels. The results of treatment of 12 patients with AVF were analyzed. In 2 (16.6%) patients Randu-Veber-Osler syndrome was diagnosed. In 10 observations the diagnosis was confirmed by the angiography data. All the patients were operated on. One (8.4%) patient died.