Barrett's esophagus (BE) is a consequence of chronic gastroesophageal reflux and is considered a risk factor for adenocarcinoma. The study of the mucus, especially acid mucins, such as the sialomucins in the goblet cells which characterize BE, showed that in intestinal metaplasia, frequent in the digestive tract, the organ's original epithelium could express Tn and Stn antigens. These antigens have already been detected in gastric and colonic tumors, however references in BE were not found. This research aimed to analyze these antigens in patients with BE and in adenocarcinoma associated with BE.Utilizing immunohistochemistry tests, Tn and Stn antigens were studied in the endoscopic biopsies of 29 patients with BE and seven with adenocarcinoma in BE, as well as eight individuals with normal esophageal epithelium at upper digestive endoscopy.The Stn antigen was positive in the goblet cells of patients with BE in 100% of the cases and the Tn was positive in 48%. In the columnar cells, Stn was always negative, while Tn was positive in 100% of the cases. However, in adenocarcinoma in BE, both antigens were 100% positive. In normal individuals, the Tn antigen was positive and the antigen Stn negative in all cases.It is probable that the BE group in which the Tn antigens in the goblet cells are positive, similarly to the same antigen in the adenocarcinoma group, might indicate a higher susceptibility for potential occurrence of cancer. In the future, trials with sialomucins could be used routinely, thereby contributing as a prognostic factor of adenocarcinoma in BE.