This study is aimed at a role of Helicobacter pylori (HP) infection in reflux esophagitis of the elderly. 46 patients with reflux esophagitis aged at older than 60 years are selected for this study with informed consent. 43 patients without reflux esophagitis, peptic ulcer, and gastric cancer are used as a control group. In reflux esophagitis, gastric mucosal atrophy is judged as closed type of endoscopic findings in all cases. In control, 27 of 43 patients were judged as open type. Serum pepsinogen I, II ratio is 4.73 +/- 1.28 which is higher significantly than 3.39 +/- 1.69 in control. Serological positive rate of HP antibody is 39.1% in reflux esophagitis. This rate is significantly lower than 62.7% in control. In conclusion, low frequency of chronic HP infection protects gastric mucosa from atrophy, and keeps secretion of gastric acid, resulting in reflux esophagitis of the elderly accompanied with various abnormal esophago-gastric functions.