Current concepts regarding the nature and the treatment of Barrett's esophagus and its complications are reviewed. The columnar-lined lower esophagus is being increasingly recognized as an acquired condition caused by gastroesophageal reflux. Many patients are asymptomatic. Barrett's esophagus occurs in about 10% to 15% of patients with reflux esophagitis. The diagnosis depends on endoscopy and biopsy. Complications are common and include ulceration, stricture, dysplasia, and adenocarcinoma. Esophagitis, ulceration, and stricture can usually be treated medically. Surgical approaches are discussed for patients whose condition is refractory to medical therapy. The premalignant nature of Barrett's epithelium is well recognized, and strategies for surveillance and resection are discussed. Survival after resection of adenocarcinoma in Barrett's esophagus is not appreciably different from that of other carcinomas. Surveillance with endoscopy offers the best chance for early detection and cure.