BACKGROUND/AIMS: Barrett's esophagus is a premalignant lesion of the esophagus in which normal squamous epithelium is replaced by intestinalized columnar epithelium. In Korea, adenocarcinoma associated with Barrett's esophagus is rare compared with that of Western country. The purpose of this study was to investigate the immunohistochemical expression of p53 and Ki-67 in Barrett's esophagus which had predictive value for cancer risk in Korea. METHODS: Ninety five patients (43 male and 52 female, median age 44, range 21-75) who have been suspected to have Barrett's esophagus by endoscopic assessment were enrolled in this study. Alcian blue (pH 2.5) and high ion diamine stain for the evaluation of specialized intestinal metaplasia (SIM) and immunohistochemical stain for p53 and Ki-67 were done. RESULTS: 57.9% (55/95) of biopsies from the columnar lined esophagus showed SIM, but no dyspalsia. 56.4% (31/55) of Barrett's esophagus showed sulfomucin positive colonic metaplasia. The p53 expression was observed in 10.9% (6/55) of the patients of Barrett's esophagus and all of them showed colonic metaplasia. Ki-67 labeling index showed no difference significantly. CONCLUSIONS: In Korea, 10.9% of Barrett's esophagus had p53 mutation and moreover all of them had colonic metaplasia. Consequently, we expect that these patients have high risk of developing dysplasia and adenocarcinoma and need careful follow-up.