During a 28-year period, 52 bronchopleural fistulas developed after pulmonary resection of 49 primary and three recurrent lung cancers at the National Cancer Center Hospital, Tokyo. During the same period there were 2359 pulmonary resections for primary lung cancer; the prevalence of bronchopleural fistula was 2.1%. Multivariate analysis on 15 variables in the most recent 1360 resections revealed significant risk factors for bronchopleural fistula: wider resection such as pneumonectomy, residual carcinomatous tissue at the bronchial stump, preoperative irradiation, and diabetes. Univariate analysis further recognized a risk in preoperative bronchial arterial infusion and the postsurgical stage of lung cancer. Six patients were not treated. Apart from chest tube drainage in seven patients, surgical repair was attempted in 39, direct resuture of the stump in 16, wrapping in 25, thoracoplasty in 31, completion pneumonectomy in 6, and other treatments. Despite various treatments, 37 patients (71.2% mortality) died from fistula-related complications (such as regurgitation of infected pleural fluid through the fistula and airway/intrathoracic bleeding). Even for patients whose fistulas were cured and who were discharged, the average hospital stay was 189 days. Further investigation is necessary to answer whether prevention by flap coverage is of any benefit.