In Japan, the first paper on endoscopic resection (ER) for squamous cell carcinoma (SCC) of the esophagus confined to the mucosa was reported as endoscopic mucosal resection (EMR) in 1988. Since publication of that article, ER has been recommended as the standard treatment for squamous and mucosal cancer of the esophagus. T1a-EP and T1a-LPM esophageal cancer seldom involves lymph node metastasis. However, in cases of T1a-MM and T1b-SM1 esophageal cancer with lymph node metastasis (10% to 30%), the indication of ER is limited. The risk factors for lymph node metastasis in T1a-MM and T1b-SM1 esophageal cancer were cleared by clinical and pathological studies. Endoscopic findings such as type 0-I or type 0-III, size of 50 mm or more, and pathological findings such as lymphatic permeation, venous permeation, poorly differentiated SCC and INFb or INFc were suggestive of high risk for lymph node metastasis. In addition, histopathological findings of small cancer nests, defined as "budding" or "droplet infiltration," suggest frequent lymph node metastasis. In cases of T1a-MM and T1b-SM1 esophageal cancer with high risk of lymph node metastasis, adjuvant therapy including chemoradiotherapy and radical esophagectomy are recommended after ER. A recent advance in ER for esophageal cancer is the establishment of endoscopic submucosal dissection (ESD). It has allowed us to perform an en-block resection of a large mucosal lesion of the esophagus and detailed histopathological examination. However, ESD requires more difficult manipulation than EMR. The indication of EMR or ESD is sought.