We experienced a case of intralobar pulmonary sequestration preoperatively confirmed. The 10 years old male patient was admitted beacuse of recurrent episode of coughing and production of purulent sputum. the chest X-ray showed a dense mass containing a large cyst with air-fiuid level in right lower lung field. An aortogram was performed and revealed that the sequestrated portion of the RLL was supplied by an aberrant large artery arising directly from the lower thoracic aorta. After division and ligation of the aberrant artery in pulmonary ligament, the right lower lobectomy was performed and the patient`s postoperative course was uneventful.