The endoscopic resection of the mucosa of the digestive tract (ERM) is a set of techniques that have as their end the remotion of the mucosa for the diagnosis and treatment of localized diseases. The technique consists of the elevation of the mucosa with a submucosa injection of liquid or with suction in the interior of a transparent overtube. The procedure is indicated in the treatment of incipient malignant tumors of the esophagus, stomach, and colon, with a success rate that vacillates between 60 and 95%. An indispensable condition is the precise selection of patients through endoscopy and high-frequency endoscopic ultrasound. Other indications are the resection of flat and sessile polyps, the biopsies of submucosa tumors, and the taking of biopsies of great volume for the study of infiltrating and inflammatory neoplastic diseases. Based on the literature, principally descriptive and not comparative, the treatment of incipient digestive tract carcinomas with ERM has encountered serious difficulties in the Western world because of the rarity of the diagnosis, the scarce availability of endoscopic ultrasound, and lack of information of long-term results. On the other hand, in the diagnostic field of mucosa diseases, and in the treatment of polyps, its utility is evident. In conclusion, ERM is added to the new endoscopic techniques for the obtaining of specimens of great volume and for the resection of sessile polyps. In the treatment of malignant tumors, ERM should be used with caution.