Abstract: From the pre-and postoperative studies of the pulmonary function and the operative findings in 105 cases of bronchiectasis treated in the author's clinic for the past ten years, the following results were obtained: the different sites of predilection of cylidrical and cystic bronchiectasis suggested the different pathogenesis of these two entities.Characteristics of pulmonary function study of this disease had been thought to be of ventilation, chiefly expiratory, disturbance, however, in the author's series the preoperative pulmonary function was within normal limit in most cases and there was a few cases with a typical pattern of obstruction.The cases showing disturbance of pulmonary function in the pre-operative examination were mostly found in the relatively old age group and the most of them had bilateral involvement of bronchiectasis.The post-operative pulmonary function of this disease showed that the first second TVC was significantly increased in contrast with that of pulmonary tuberculosis. Postoperative result in 6 months showed a cure or improvement of the disease in 91% of the cases, and long-term results showed improvement of symptoms in approximately 90%.The author stressed that surgical treatment should be indicated after clinical signs and pulmonary function were taken account of rather than the type and extension of brochiectatic change in the lung.