Congenital thoracic malformations such as intra- and extra-pulmonary sequestration, cystic adenomatoid malformation, congenital pulmonary airway malformation, malinosculation, bronchogenic cyst, reduplication cyst, and foregut cyst are frequently detected on routine prenatal ultrasound. There are some controversies about treatment for postnatally persistent pulmonary sequestration. Some authors recommend expectant long term follow up but most authors advocate elective surgical excision because of complication such as respiratory distress, infection, intrathoracic bleeding, haemoptysis, cardiac failure, and potential risk of malignancy. We experienced 2 cases of prenatally diagnosed extrapulmonary sequestration which were located in the subdiaphragmatic retroperitoneum. Resections were performed at 2 months and 4 months of age using intraabdominal approach. There were no complications. In conclusion, if the prenatally diagnosed extrapulmonary sequestration remained postnatally, early operation might reduce morbidity related to extrapulmonary sequestration and parental anxiety without any postoperative complication.