Barrett's esophagus is a premalignant metaplastic change in the lining of the distal esophagus. It represents a peculiar form of healing which occurs in response to chronic gastroesophageal reflux. The etiology of this condition is unknown but clinical and experimental data points to esophageal exposure to duodenal juice as the key factor in its development. Barrett's esophagus should be considered in all patients undergoing endoscopy for symptoms of reflux disease. It is confirmed by the presence of intestinal metaplasia in an area of columnar mucosa, regardless of the macroscopic appearances of the distal esophagus. Endoscopic surveillance with multiple biopsy of the columnar mucosa is indicated for all medically fit patients with Barrett's esophagus. Identification of intestinal metaplasia with high-grade dysplasia heralds the development of invasive cancer and offers the physician an opportunity to intervene. Esophagectomy is the treatment of choice for patients with high-grade dysplasia, since occult early adenocarcinoma is identified in up to 50 percent of the esophageal specimens.