Barrett’s esophagus is formed when the squamous epithelium of the esophageal mucosa is replaced by a metaplastic columnar epithelium during the repair process of the damaged tissue. Studies have shown that Barrett’s esophagus is not only associated with the appearance of GERD symptoms, but also with the duration of symptoms, with the longer the duration, the higher the incidence of Barrett’s esophagus. Numerous studies have shown that Barrett’s esophagus is the most important factor in the development of esophageal adenocarcinoma. Studies have shown that the risk of esophageal adenocarcinoma in patients with Barrett’s esophagus is 30-60 times higher than in normal subjects. The incidence of Barrett’s esophagus in esophageal adenocarcinoma was found to be 100%. The higher the frequency of heartburn, the greater the correlation with esophageal adenocarcinoma, and the duration of heartburn >20 years is significantly associated with the development of esophageal adenocarcinoma, but not with squamous esophageal cancer or adenocarcinoma of the esophagogastric junction. Thus, chronic GERD is not only associated with Barrett’s esophagus, but also with esophageal adenocarcinoma. The exact pathogenesis of adenocarcinoma of Barrett’s esophagus is still not well understood.