Background : Anti-reflux procedures treat gastroesophageal reflux (GER) disease. It is known that gastroesophageal reflux is likelyrelated to the increased incidence of chronic rejection in lung transplantation recipients. Because experimental animal studies areto verify this, we have tried to make an animal model of GER in a rat. Material and Methods : Using the SD rats weighing 250-300 g, we surgically induced gastroesophageal reflux and measured the gastrostomy time under anesthesia. Of three groups, Group I was the control, Group II had lower esophageal and anterior myotomy, and Group III had lower esophageal and anterior myotomy plusdiaphragmatic crural myotomy.The animals were scarified, and lung biopsies and histological examinations were performed 1 week, 2 weeks, 4 weeks, 8 weeks and 3 months after gastroesophageal reflux surgery. Results : Baseline animals (n=5) had no GER after charcoal instillation through a gastrostomy tube in Group I. Charcoal-laden macrophages were observed in GroupsII and III. To determine evidence of GER evidence, charcoal was instillated through the gastrostomy tube in group III. In contrast, Group II demonstrated severe neurophil infiltration in the bronchioles and alveolar walls after procedure. After 12 weeks, we observed the disappearance of neurophil, lymphocyte and histiocyte infiltration, and also occasional focal bronchopneumonia and bronchitis. Group III demonstrated neurophil and basophil infiltration in the bronchioles and alveolar walls which was more severe than that in Group II. Interstitial fibrotic changes were observed in Group III.Conclusion : The purpose of our gastroesophageal reflux model was to find evidence of aspiration. There was more evidence of aspiration in Group II than in either of theother two groups.