Barrett's oesophagus is a complication of gastro-oesophageal reflux disease and should be considered as a major risk factor for the development of adenocarcinoma of the oesophagus. Each and every patient with Barrett's oesophagus should be enrolled in a endoscopic surveillance program. During the last years, the endoscopic treatment of high grade dysplasia or intramucosal adenocarcinoma (by mucosectomy) has been reported to be successful in relatively large series of patients. This therapeutic option is particularly useful for patients with a high operative risk. It can be applied for lesions detected at an early stage only (i.e., usually detected in the setting of a surveillance program). Therefore, non-operability is not considered as an exclusion criteria of such programs anymore.