Barrett's esophagus represents an epithelial metaplasia in which a columnar lining replaces normal squamous epithelium of the esophagus. It occurs in at least 10% of patients with chronic gastroesophageal reflux and is associated with an increased risk of adenocarcinoma of the esophagus. This review focuses on the criteria for the diagnosis of Barrett's esophagus, discusses its association with adenocarcinoma, and provides guidelines for surveillance for carcinoma.