Background : A diaphragmatic hernia is defined as a communication between the abdominal and thoracic cavities with or without abdominal contents in the thorax. The specific cause is thought to result failure of closure of the pleuroperitoneal canal in the developing fetus. For this reason, Bochdalek hernia commonly seen in the newborn period. But delayed form of Bochdalek hernia has also been reported. We report one infant was diagnosed Bochdalek hernia at 9 month old with normal chest x-ray at birth. Case report : A 9-month-old girl was referred to our hospital because of recent complaints of dyspnea, lip cyanosis at feeding, cough and vomiting. In past medical history, she was admitted to our neonatal intensive care unit at birth due to transient tachypnea of the newborn.(TTN) At that time she was taken chest X-ray, which was not abnormal finding, except finding of TTN. The infant admitted our pediatric unit under the diagnosis of pneumonia at this time. Vital sign was stable. Physical examination revealed decreased breath sound with rales in right middle lung field. Initial chest X-ray showed infiltration in right middle lobe and it was suspected that bowel gas located in left lower hemithorax. We took a chest computerized tomography(CT) under suspected diaphragmatic hernia. CT finding shows herniated colonic loop into the left hemithorax and defeat in the lateral and posterior of the diaphragm. The patient was operated at hospital day 17 after sufficient care about pneumonia. The operation on 3 thoracoscopic port inserted at left chest wall and reduction of large bowel using bowel grasper. Primary repair of diaphragm defect was done. The postoperative course was uneventful, and the patient was discharged on postoperative day 13. The patient has been symptom free during a 3-month follow up period. conclusion : Late presenting Bochdalek hernia can present with acute or chronic gastrointestinal, or less frequently, respiratory symptom. Diaphragmatic hernia should be considered in any child presenting with respiratory distress, although the previous chest x-ray was normal.