The authors describe 5 cases of bi-apical pulmonary fibrosis occurring during the course of ankylosing spondylitis. In 4 patients the lesions were advanced and detected during pneumological investigations. In the 5th patient, the lesions were at an early stage and were discovered during a retrospective study of 100 case-reports of patients with ankylosing spondylitis. Radiological signs were morphologically similar: localized pulmonary lesions of the two apices, of the retractile type and with a fibrous hilar framework, bullous images that were more or less extensive, raising of the two hili with compensatory distention at both bases, and pleural lesions consisting of thickening of both pleurae at the apices. The mean age of the patients at the time these lesions appear is 60 years, and they occur about 20 years after the onset of the articular disorder. These fibro-bullous lesions can be complicated by aspergillosis (20%) of pneumothorax (8%). The principal differential diagnosis is advanced tuberculous disease in the lung apices, and this explains why these patients have often been prescribed antituberculosis therapy.