Pulmonary sequestration is applied to the congenital malformation characterized by an area of embryonic lung tissue that derives its blood supply from an anomalous systemic artery. Two cases of pulmonary sequestration were treated at the department of thoracic and cardiovascular surgery, college of medicine, Hallym University. One case was extralobar type, associated with the pneumothorax due to rupture of bulla. The other was intralobar type with symptom of massive and recurrent hemoptysis. The supplying arteries of both cases arose from the thoracic aorta. The venous return of the extralobar type was systemic into the hemiazygos vein, and that of the intralobar type was normal into the inferior pulmonary vein. Treatment for the former was resection of the sequestrated lung, and that for the latter was lobectomy of the left lower lobe. With the brief review of literature, we report the cases.