The importance of endoscopic evaluation and grading of the gastroesophageal flap valve (GEFV) in patients with gastroesophageal reflux disease (GERD) was previously demonstrated with increased acid exposure and high grades of esophagitis in those with high-grade valves. On the other hand, no data exist on the relationship between GEFV appearance and surgical rate.For 453 patients with symptoms suggestive of GERD, GEFV grading and 24-h ambulatory pH monitoring were performed. Surgery was performed for 82 of these patients who failed medical management or had disease complications.The GEFV grade 4 patients were younger than the patients with normal GEFV (grades 1 [p = 0.017] and 2 [p < 0.001]) and showed significant male predominance. The prevalence of hiatal hernia, the degree of esophageal acid exposure, and the prevalence and degree of erosive esophagitis significantly increased with GEFV grade (p < 0.001 for all). No GEFV grade 1 patients underwent surgery compared with 4.9 % of the grade 2 patients, 20.5 % of the grade 3 patients, and 63.6 % of the grade 4 patients who had surgery for various indications (p < 0.001).Esophagogastric opening estimated by endoscopic grading of the GEFV was strongly correlated with surgery rate in GERD patients. In particular, patients with grade 4 valves showed the highest rates of erosive esophagitis and axial hiatal hernia and frequently underwent surgery for either failed medical management or disease complications.