AIM: To evaluate the significance of the composite score of reflux symptoms in the diagnosis of gastroesophageal reflux disease (GERD), and to determine the relationship of the composite score with reflux esophagitis (RE) and pathological gastroesophageal reflux (PGER).METHODS: Upper digestive endoscopy and /or 24-h esophageal pH monitoring were performed in 244 subjects.Of these, 54 were consecutive patients attending our clinic with symptoms suggestive of GERD, and 190 were randomly selected from 2532 respondents who participated in our previous general population-based study on GERD. A standardized questionnaire was used to classify both the frequency and severity of typical symptoms of GERD(heartb, acid and food regurgitation) using a 4-score scale, and the composite score of main reflux symptoms(score index: SI, range from 0 to 18) were calculated for every subject. RE was diagnosed according to the SavaryMiller criteria. Subjects with abnormal pH-metry (DeMeester score more than 14.7) were considered to have PGER.GERD patients were defined as the subjects with RE and/or PGER.RESULTS: The sensitivity of SI in the diagnosis of GERD was inversely associated with SI, but the specificity tended to increase with increased SI. With the cut-off of 8, the SI achieved the highest accuracy of 70.0%, with a sensitivity of 78.6% and a specificity of 69.2% in diagnosing GERD,followed by the cut-off of 3, which had an accuracy of 62.1%,a sensitivity of 96.4% and a specificity of 34.6%. The prevalence of RE, PGER and GERD was strongly associated with increased SI (P＜0.01), but there was no significant association between the severity of RE and SI (P＞0.05).Among patients with RE, 69.2% had PGER, and 30.8%were confirmed to have negative findings of pH monitoring.Among patients with PGER, 52.9% were identified to have RE and 47.1% had negative endscopic findings in esophagus.CONCLUSION: According to the composite score of main reflux symptoms, the diagnosis of GERD can be made without further tests in most cases. However, 24-h esophageal pH monitoring and upper digestive endoscopy are still indicated in patients with mild and atypical symptoms.