The key issue in the field of therapeutic endoscopy in recent years is the development of a new therapeutic strategy for early gastric cancers using endoscopic submucosal dissection (ESD) technique. ESD was developed to overcome the problem of remnant or recurrent tumors after incomplete resection by conventional endscopic mucosal resection (EMR). Ever since after the emergence of ESD, indication criteria for endoscopic resection of early gastric cancers were extended through expansion of both theoretical and technical conditions. Complete en bloc resection rates were 96.7% and 62.6% in the ESD group and the EMR group, respectively, in our institution. ESD is a highly effective technique enabling us to resect much larger and difficult lesions, which cannot be resected by conventional EMR techniques. However, it involves a much higher complication rate and requires much higher skills. A small lesion less than 20 mm located in a good position can be resected completely, without any difficulties using conventional EMR techniques. Therefore, we must consider the approach to treatment, when conducting an endoscopic resection,it terms of the situation and skills of the endoscopist.