Gastroesophageal reflux disease (GERD), which is commonly encountered in clinical practice, has become increasingly prevalent in Asia in recent years. Definitive diagnosis of GERD requires upper gastrointestinal endoscopy and ambulatory pH monitoring and is therefore challenging. Endoscopic lesions are usually not incorporated into the diagnostic criteria, and pH monitoring is expensive, complicated, and uncomfortable for patients. Studies have investigated novel methods for diagnosis of GERD. Mucosal integrity, evaluated by mucosal admittance or impedance, is impaired in GERD owing to microscopic epithelial changes. Measurement of mucosal integrity is simple and can be performed endoscopically. Mucosal impedance has been investigated as a method to differentiate between GERD, non-GERD, and eosinophilic esophagitis, and mucosal admittance provides evidence to support diagnosis of GERD. Further research on these novel techniques is warranted to incorporate these into the diagnostic modalities used for GERD.