Barrett's esophagus is most often seen in white men with chronic heartburn who are generally older than 50 years of age. The prevalence of Barrett's esophagus is 10% to 15% in patients who are undergoing endosocopy for gastroesophageal reflux disease and 1% to 2% in asymptomatic American adults. Barrett's esophagus represents metaplastic columnar tissue with specialized intestinal metaplasia, and this condition carries an increased risk of esophageal adenocarcinoma. Patients with Barrett's esophagus have a risk of esophageal adenocarcinoma 30 to 60 times that of the general population with an incidence rate of over 100 times that of the general population. Esophageal adenocarcinoma has increased dramatically over the past few decades with specialized intestinal metaplasia being the most important risk factor for the development of dysplasia and cancer. Barrett's esophagus develops in the presence of persistent gastroesophageal reflux, which is an independent risk factor for adenocarcinoma. Other risk factors for adenocarcinoma in patients with Barrett's esophagus include length of Barrett's epithelium, low-grade dysplasia, and high-grade dysplasia. New data concerning the pathophysiology and biology of Barrett's epithelium may provide answers to prevent or treat esophageal cancer. This article briefly reviews Barrett's esophagus and focuses on the risk factors associated with its progression to adenocarcinoma.