BACKGROUND/AIMS: There were few epidemiological data on reflux esophagitis in Korea. The aim o this study was to estimate the prevalence and risk factors of reflux esophagitis in Korea. METHODS: We examined 8314 subjects (male 4,876, female 3,438, age: 18-83 year) visiting health promotion center for routine check-up including EGD. All of them were given a questionnaire about smoking alcohol consumption, exercise, diet habits, use of drugs and medical history. We estimated the prevalence of reflux esophagitis and performed a case-control study to evaluate the risk factors of reflux esophagitis. We recruited 200 cases with reflux esophagitis and 400 controls without reflux esophagitis on EGD. RESULTS: The prevalence of reflux esophagitis was 3.73% in male and 0.81% in female. The age-adjusted prevalence was 3.19% in male and 1.66% in female. The prevalence in male was significantly higher than that in female (p<0.01). On the monovariate analysis, smoking and body mass index were significantly related with reflux esophagitis (p<0.05). On the multivariate analysis, smoking was a significant risk factor of reflux esophagitis (p<0.05). CONCLUSIONS: The prevalence of reflux esophagitis in subjects who had routine check-up was 3.73% in male and 0.81% in female. Smoking is suggested to be a significant risk factor of reflux esophagitis.