Adenocarcinoma of the distal esophagus is rising more rapidly in incidence than any other visceral malignancy in the Western world. It is well established that most, if not all, of these tumors develop in Barrett's esophagus via the metaplasia-dysplasia-carcinoma sequence and could theoretically be detected at an early stage, but despite this, the majority of these tumors are still detected late in their course. This highlights the fact that the goal of effective surveillance for patients at risk for developing an adenocarcinoma of the distal esophagus is still far off. In addition, adenocarcinomas of the esophagogastric junction and gastric cardia are also rising in incidence, but their carcinogenesis and their relation to Barrett's esophagus are still being defined, as are the meaning and significance of the relatively new entities "short-segment Barrett's" and "ultra-short-segment Barrett's". This review attempts to clarify the main histopathologic issues concerned with the definition of Barrett's esophagus, its distinction from intestinal metaplasia of the gastric cardia, as well as the criteria for the histologic diagnosis of dysplasia and carcinoma in Barrett's esophagus.