Endoscopic Submucosal Dissection (ESD) has recently become a widely accepted treatment for premalignent lesions of the stomach and early gastric cancer. Post-ESD stenosis is a rare complication of ESD, but this can be caused by the removal of a large lesion when lesions are located near the cardia or pylorus. We experienced two cases of post-ESD stenosis. One developed in a high risk patient and this was treated by repeated balloon dilation. The other occurred in a patient who was without risk factors, but the stenosis improved spontaneously. It is important that we should perform early follow-up endoscopy in patients who are at a high risk for post-ESD stenosis, and administer effective treatment. (Korean J Gastrointest Endosc 2010;40:261-265)