Endoscopic mucosal resection was introduced in the 1990s, and endoscopic submucosal dissection (ESD) in 2003. Currently, ESD is becoming the main procedure for the resection of early gastric cancer (EGC) and is leading to the development of extended indications for endoscopic resection. Many reports showed that the endoscopic and oncologic outcome of endoscopic treatment in the extended indication group was acceptable in terms of curability and safety. Especially, ESD showed better results to remove extended indication EGCs with relatively high resection rate and low local recurrence rate. However, more long-term follow-up data are needed for clinical application of the extended criteria of ESD due to the risk of lymph node metastasis. We should also keep in mind that accurate diagnosis, characterization of the lesion, and proper appreciation of technical aspects are most essential in therapeutic endoscopy.