Diaphragmatic hernia complicating pregnancy is rare and is associated with high morbidity and mortality, particularly if surgical intervention is delayed. We report a case of diaphragmatic hernia in a pregnant 25-year-old woman. The patient was referred to our hospital in respiratory distress in the 28th week of her pregnancy. Chest radiograph and computed tomography showed air-filled bowel loops in the left side of the chest, with a marked mediastinal shift. Immediately after an emergency caesarean section, the herniated abdominal viscera were reduced through the opening in the diaphragm. We resected the ischemic segment of ileum and repaired the diaphragmatic defect with interrupted sutures and a Gore-Tex sheet. She had an uneventful postoperative course and her baby boy also recovered well. We report this case to alert surgeons to the possibility of this rare surgical emergency during pregnancy.