Objective : Reflux esophagitis (RE) is often seen in obese patients on endoscopy. This study investigated the prevalence of RE caused by obesity. Participants : A total of 794 subjects was investigated, consisting of 246 women and 548 men. Methods : Body mass index (BMI) was modified by the criterion of Japan Society for the Study of Obesity (JASSO), and RE on endoscopy was evaluated by the Los Angeles Classification. Results : The prevalence ratio of RE (women : men) was 1.5 : 2.2 at 25?BMI < 27.5, and 2.0 : 2.7 at 27.5?BMI in adults, and 1.9 : 2.4 at BMI < 20, 0.9 : 1.8 at 20?BMI < 22.5, 2.2 : 1.9 at 22.5?BMI<25, 2.5 : 2.6 at 25?BMI<27.5 and 2.8 : 3.1 at 27.5?BMI in the elderly compared with 20?BMI < 25 in adults. Conclusions : There was a higher frequency of RE in more obese subjects and also in the elderly. RE should be kept in mind for improvement of life style including antireflux measures to manage these factors.