A giant hiatal hernia (HH) is a hernia that includes at least 30% of the stomach in the chest, although a uniform definition does not exist; most commonly, a giant HH is a type III hernia with a sliding and paraesophageal component. The etiology of giant HH is not entirely clear, and two potential mechanisms exist: (1) gastroesophageal reflux disease (GERD) leads to esophageal scarring and shortening with resulting traction on the gastroesophageal junction and gastric herniation; and (2) chronic positive pressure on the diaphragmatic hiatus combined with a propensity to herniation leads to gastric displacement into the chest, resulting in GERD. The short esophagus and GERD are key concepts to under-standing the pathophysiology of giant HH, and these concepts are critical to address this problem appropriately. A successful repair of giant HH requires adherence to basic hernia repair principles (ie, hernia sac excision, tension-free repair), recognition and correction of a short esophagus, and a well-performed antireflux procedure. Recurrence rates for open giant HH repairs in expert hands range between 2% and 12%; large series have demonstrated that meticulous laparoscopic surgical technique can emulate the results of open giant HH repair. (Ann Thorac Surg 2010; 89: S2168-73) (C) 2010 by The Society of Thoracic Surgeons