AIM:To examine the prevalence of gastroesophageal reflux disease (GERD) symptoms in a large unselected general population in Japan. METHODS: In Japan, mature adults are offered regular check-ups for the prevention of gastric cancer. A notice was sent by mail to all inhabitants aged > 40 years. A total of 160 983 Japanese (60 774 male, 100 209 female; mean age 61.9 years) who underwent a stomach check up were enrolled in this study. In addition, from these 160 983 subjects, we randomly selected a total of 82 894 (34 275 male, 48 619 female; mean age 62.4 years) to evaluate the prevalence of abdominal pain. The respective subjects were prospectively asked to complete questionnaires concerning the symptoms of heartburn, dysphagia, and abdominal pain for a 1 mo period. RESULTS: The respective prevalences of the symptoms in males and females were: heartburn, 15.8% vs 20.7%; dysphagia, 5.4% vs 7.8%; and abdominal pain, 6.6% vs 9.6%. Among these symptoms, heartburn was significantly high compared with the other symptoms, and the prevalence of heartburn was significantly more frequent in females than in males in the 60-89-year agegroup. Dysphagia was also significantly more frequent in female patients. CONCLUSION: The prevalence of typical GERD symptoms (heartburn) was high, at about 20% of the Japan population, and the frequency was especially high in females in the 60-89 year age group. AIM: To examine the prevalence of gastroesophageal reflux disease (GERD) symptoms in a large unselected general population in Japan. METHODS: In Japan, mature adults are offered regular check-ups for the prevention of gastric cancer. all inhabitants aged> 40 years. A total of 160 983 Japanese (60 774 male, 100 209 female; mean age 61.9 years) who underwent a stomach check up were enrolled in this study. selected a total of 82 894 (34 275 male, 48 619 female; mean age 62.4 years) to evaluate the prevalence of abdominal pain. The individuals were prospectively asked to complete questionnaires concerning the symptoms of heartburn, dysphagia, and abdominal pain for a 1 mo period. RESULTS: The positive prevalences of the symptoms in males and females were: heartburn, 15.8% vs 20.7%; dysphagia, 5.4% vs 7.8%; and abdominal pain, 6.6% vs 9.6% significantly high comp ared with the other symptoms, and the prevalence of heartburn was significantly more frequent in females than in males in the 60-89-year age group. Dysphagia was also significantly more frequent in female patients. CONCLUSION: The prevalence of typical GERD symptoms (heartburn) was high, at about 20% of the Japan population, and the frequency was particularly high in females in the 60-89 year age group.