Chronic diaphragmatic hernia is a rare entity and requires surgical intervention when it is diagnosed. We report three patients with chronic diaphragmatic hernia that followed a diagnosis of diaphragmatic abnormality with no previous chest injury. Operative findings suggested a diaphragmatic defect in a congenitally weak area. All patients were satisfied with the resolution of their preoperative discomfort and their improved respiratory function after repair using Marlex mesh sheets via thoracotomy and laparotomy. Chronic diaphragmatic hernia should be considered even in patients who had no previous chest injury.