During a 25-year period 69 patients whose ages ranged from 1 day to 64 years were treated for bronchogenic cyst of the mediastinum. The male-to-female sex ratio was 1:0.76. The cysts were symptomatic in 63.7%, compressive in 43.4%, and life threatening in 2.8% of cases. Symptoms and signs of compression were more frequent in infants and children than in adults. Such symptoms and signs were more dependent on the location of the cyst than on its volume. The preoperative diagnosis was wrong in 16% of cases. The cysts were approached through thoracotomy in 67 cases, including one conversion from thoracoscopy, and through cervicotomy and mediastinoscopy in one case each. The cysts opened into the respiratory tract in five cases. No communication with the esophageal lumen was observed. The cystic contents were apparently infected in three cases, but samples remained sterile at culture. There was one hospital death caused by a centrally located compressive cyst that was undiagnosed at thoracotomy. The postoperative morbidity rate was 13.4%. There were no further symptoms after operation in children, but five adults reported continuing pain or dyspnea. Resection of bronchogenic cysts is recommended because of uncertainties in diagnosis and in evolution.