Extracorporeal membrane oxygenation (ECMO) support has improved the outlook for some infants who have large diaphragmatic hernias (CDH). This has resulted in a subset of survivors of CDH with typically larger defects, more severe pulmonary hypoplasia, and more associated pathologies. This report describes the authors' experience with gastroesophageal reflux in patients with large diaphragmatic hernias who require ECMO. Contrary to previous reports, this reflux was severe and intractable. There appears to be a component of associated gastric dysmotility. In treating this reflux, medical therapy and anterior fundoplication were not successful, and Nissen fundoplication combined with pyloroplasty was required to control reflux and to allow gastric feeding. On the basis of the authors' experience, it is recommended that patients who have gastroesophageal reflux after CDH repair, for whom medical management has failed, be managed aggressively by surgery, with early Nissen fundoplication, and pyloroplasty and insertion of a gastric feeding tube.