Barrett's esophagus, a condition in which the distal esophagus is lined by columnar epithelium, is almost always caused by gastroesophageal reflux and often occurs in conjunction with a sliding hiatal hernia. Patients are typically white men in their 50s who smoke and drink, and they present with complaints of regurgitation, heartburn, and/or dysphagia. Endoscopic biopsies are required to confirm the diagnosis. Complications, such as stricture, ulcer, dysplasia, and malignant degeneration, occur in many cases. Adenocarcinoma is the most serious complication. Medical treatment, including life-style changes as well as pharmacologic therapy, usually relieves symptoms and heals esophagitis, but when it fails, antireflux surgery is indicated. Patients without evidence of dysplasia should undergo endoscopy yearly; those with mild dysplasia require more frequent surveillance. If biopsies disclose severe dysplasia, esophagogastrectomy should be performed.