Background. We assessed the characteristics of symptomatic gastroesophageal reflux disease (sGERD), defined as the presence of symptoms, but no endoscopic findings of reflux esophagitis, in Japanese. Methods. Sixty- three patients were diagnosed with sGERD, and underwent 24- h esophagogastric pH monitoring (32 men; mean age, 50.5 years). Patients were classified into the following three groups: reflux group (group R), minor reflux group (group MR), and a no- reflux group (group N) by the percentage of time at pH below 4 (group R, 4.0% or more; group MR, 2.0% - 3.9% ;groupN, 0- 1.9% ). Hiatal hernia was assessed based on the Anatomy- Function- Pathology (AFP) classification, and the shape of the cardia was assessed based on valve factors (V0- V3). Results. There were 13 patients (21% ) in group R, 17 (27% ) in group MR, and 33 (52% ) in group N.Hiatal hernia was present in 11 patients (85% ) in group R, 14 (82% ) in group MR, and 22 (67% ) in group N. Patients grouped according to presence of V2/V3 (chalasia) accounted for 100% of those in group R, 71% of those in group MR and 70% of those in group N. Hiatal hernia was present in 10 (91% ), 10 (83% ), and 6 patients (86% ) who had 50 or more episodes of esophageal acid reflux per day in group R, group MR, and group N, respectively. Conclusions. Reflux (percentage of time below pH 4, 4% ) was seen in only about 20% of the patients with sGERD, and this percentage of patients with reflux was lower compared to the data reported from the United States and Europe. The percentage of patients who had a hiatal hernia or chalasia was high in all these groups, and this seemed to be a characteristic cause of sGERD in Japanese. Background. We assessed the characteristics of symptomatic gastroesophageal reflux disease (sGERD), defined as the presence of symptoms, but no endoscopic findings of reflux esophagitis, in Japanese. Methods. Sixty- three patients were diagnosed with sGERD, and underwent 24- h esophagogastric The patients were classified into the following three groups: reflux group (group R), minor reflux group (group MR), and a no-reflux group (group N) by the percentage of time at pH below 4 (group R, 4.0% or more; group MR, 2.0% -3.9%; group N, 0-1.9%). Hiatal hernia was assessed based on the Anatomy- Function- Pathology The shape of the cardia was assessed based on the valve factors (V0-V3). Results. There were 13 patients (21%) in group R, 17 (27%) in group MR, and 33 (52%) in group N. Hiatal hernia was present in 11 patients (85%) in group R, 14 (82%) in group MR, and 22 (67%) in group N. Patients grouped according to prese nce of V2 / V3 (chalasia) accounted for 100% of those in group R, 71% of those in group MR and 70% of those in group N. Hiatal hernia was present in 10 (91%), 10 (83%) , and 6 patients (86%) who had 50 or more episodes of esophageal acid reflux per day in group R, group MR, and group N, respectively. Conclusions. Reflux (percentage of time below pH 4, 4%) was seen in only about 20% of the patients with sGERD, and this percentage of patients with reflux was lower compared to the data reported from the United States and Europe. The percentage of patients who had a hiatal hernia or chalasia was high in all these groups, and this seemed to be a characteristic cause of sGERD in Japanese.