Pulmonary sequenstration, defined as loss of connection of the lung tissue with bronchial tree and with pulmonary artery receiving its artery supply from the systemic artery, is very rare congenital pulmonary disease. It presents as two types, intralobular or extralobular differentiated by its location. 6 cases of pulmonary sequestrations have been diagnosed in Seoul National University Hospital. 5 cases were confirmed pathologically after lobectomy. 1 case was diagnosed with cardiac cineangiomgram only. The results are as follows: 1. 4 cases had clinical histories of pulmonary sepsis. 2 cases had cardiac problems without suspicion of the lung problem 2. 4 cases are male and 2 cases are female. 3. 4 cases angiographically confirmed preoperatively, 2 cases had no suspicion of pulmonary sequestration preoperatively. 5. 3 cases are associated with cardiovascular anomalies such as right sided aortic arch, pulmonary stenosis, complicated heart disease. 6. 5 cases-operatively proven-have intralobar types with cysitc change. 7. CT was performed in one case who shows left lower lobe area mass with air bronchogram.