Most available information on the epidemiology of Barrettacute;s esophagus (BE) relates to patients with long segments (> 3 cm) of specialized intestinal metaplasia (SIM). Its prevalence is 3% in patients undergoing endoscopy for reflux symptoms and 1% in those undergoing endoscopy for any clinical indication. The latter prevalence is similar to the 1% found in autopsy series. A "silent majority" with BE remain unrecognized in the general population. BE is more common in men, and the prevalence rises with age. Recent endoscopic series document a rise in the diagnosis of endoscopically apparent short segments (< 3 cm) of BE (SSBE). The prevalence of SSBE in both unselected and reflux patients is 8% to 12%. Specialized intestinal metaplasia at the cardia, below a normal-appearing squamocolumnar junction, has been reported to vary from 6% to 25% in patients presenting for upper endoscopy. Unlike patients with long segment Barrett's esophagus (LSBE), the role of gastroesophageal reflux disease in the pathogenesis of SSBE and SIM of the cardia is controversial. Recent data suggest that the etiology of SIM of the cardia might be secondary to Helicobacter pylori infection, although the role of other environmental factors cannot be ruled out. The incidence of adenocarcinoma of the esophagus and esophagogastric juction (EGJ) has been increasing over the past 15 years in Western countries. Surgical series and population-based studies show that by 1994 adenocarcinomas of the esophagus accounted for half of all esophageal cancer among white men. LSBE and SSBE predispose to the development of adenocarcinoma of the esophagus and EGJ. The role of SIM of the cardia as a precursor lesion for EGJ adenocarcinoma is still unclear. The prevalences of dysplasia in LSBE and SSBE are around 6% and 8%, respectively. The incidence of adenocarcinoma in patients with LSBE is about 1 in 100 patient-years. Cancer risk for SSBE and SIM at the cardia is unknown. Smoking and obesity increase the risk for esophageal and EGJ adenocarcinomas.