Background and aims Majority of patients with gastro-esophageal reflux disease (GERD) were non-erosive reflux disease (NERD). High definition (HD) endoscopy with i-scan could enhance visualization of mucosal and vascular pattern and might identify changes that were invisible at standard endoscopy. This study aimed to evaluate the endoscopic findings that may have diagnostic value for the prediction of NERD by using HD endoscopy with i-scan.