BACKGROUND/AIM: Sedated endoscopy performed for higher compliance requires close monitoring and long recovery time. In addition, several side effects including even mortality could occur. This study was performed to evaluate the usefulness of unsedated 6.5 mm endoscopy compared with sedated standard endoscopy. METHODS: One hundred eight patients were randomized into 2 groups (unsedated or sedated); unsedated endoscopy with 6.5 mm endoscope (58 patients); sedated endoscopy with standard endoscope (50 patients). Vital sign, time to recover walking ability and degree of amnesia were evaluated. The endoscopists' and patients' satisfaction and complication were estimated in terms of endoscopic score, visual analogue scale and complication score. RESULT: Oxygen saturation during the procedure significantly decreased in the sedated group. No difference was noted in endoscopists' and patients' satisfaction, but complication score was significantly decreased in the 6.5 mm scope group. The time for the induction of sedation was 3.4 minutes and the time to recover through walking ability was 36 minutes. CONCLUSION: From these results, there was no difference in either the endoscopists' or the patients' satisfaction between two groups, but complication and recovery time were significantly reduced in 6.5 mm group. Unsedated 6.5 mm endoscopy could be considered as a substitution for the sedated standard endoscopy.