A total of 69 patients were treated for congenital lung cysts at Seoul National University Hospital during the period between 1960 and Aug, 1989. They were 37 patients of bronchogenic cyst, 18 patients of pulmonary sequestration, 7 patients of congenital cystic adenomatoid malformation [C.C.A.M.], and 7 patients of congenital lobar emphysema. In cases of bronchogenic cyst, involved age was variable from 7 months to 53 years and most cases were asymptomatic. They were located 14 cases in the right lung, 6 cases in the left lung and 17 cases in the mediastinum. Their sizes were also variable from 2.5 to 12 cm and most of them except 3 cases were solitary cysts. There were 6 cases that had bronchial communication. In cases of pulmonary sequestration, aged from 3 months to 29years, all were intrapulmonary type. 15 cases of them were found in the left lower field and 3 cases in the right lower field. Anomalous vessels were confirmed in 16 cases by aortography and/or surgical exploration. In cases of congenital cystic adenomatoid malformation, aged from 7 days to 6 years, 3 cases of infants were admitted due to severe dyspnea and cyanosis but the remaining 4 cases were admitted due to large cyst or abscess on chest roentgenogram. 3 cases were located in the right lung and 4 cases in the left lung. In cases of congenital lobar emphysema, aged from 14 days to 11 years, 6 cases were located in the right lung and one case was located in the left lung. All of them were male and had shown some degree of dyspnea from birth There were 2 cases of mortality, one in C.C.A.M and one in congenital lobar emphysema. But the remaining cases were well treated and recovered with the surgical resections.