Although a variety of antireflux procedures and medications are used to treat gastroesophageal reflux disease (GERD), reliable large-animal models of GERD that can be used to objectively compare the efficacy of these treatments are lacking.Esophageal manometry and 24-h gastroesophageal pH monitoring with event data were performed in 18 mongrel dogs with a cervical esophagopexy. We then calculated a modified DeMeester score: The Duke Canine reflux score (DCR). Thereafter, the animals underwent a 4-cm anterior distal esophageal myotomy, incision of the left diaphragmatic crus, and intrathoracic gastric cardiopexy. Postoperative 24-h pH and manometry were obtained 2 weeks later.The postoperative 24-h pH results showed a significant increase in the mean DCR score (5.9 +/- 4.5 vs 84.9 +/- 56.1, p < 0.0002), and manometry indicated a significant decrease in mean lower esophageal sphincter (LES) pressure (7.1 +/- 2.9 vs 3.2 +/- 2.5 mmHg, p < 0.0001).This technique reliably creates a canine model of GERD.