It is reported that ultra-thin transnasal esophagogastroduodenoscopy (TN-EGD) reduces pharyngeal discomfort and is more tolerable for the patients. Ultra-thin transnasal endoscopy has been reported as inferior to transoral conventional EGD (TO-EGD) in terms of image quality, suction, air insufflation and lens washing, due to the smaller endoscope caliber. TN-EGD should be conducted slowly, with short distance observation, and also with image-enhanced endoscopy. With reference to image-enhanced endoscopy, chromoendoscopy method (indigocarmine) is suitable for gastric neoplasm, on the other hand optical digital method (NBI) and digital method (i-scan, FICE) is suitable for esophageal neoplasm. TN-EGD is applied in various gastrointestinal (GI) procedures such as percutaneous endoscopic gastrostomy, nasoenteric feeding tube placement, endoscopic retrograde cholangiopancreaticography with nasobiliary drainage, long intestinal tube placement in small bowel obstruction, esophageal manometry.