Barrett's mucosa consists of metaplastic columnar epithelium (specialized columnar epithelium) of the esophagus. Recently, "short-segment Barrett's esophagus (SSBE)" was proposed. In the present study, we examined immunohistochemical mucin expression and the Ki-67 labeling index (LI) of SSBE, in 5-15 mm lengths. All 27 SSBE cases showed gastric mucin (MUC5AC, HGM, MUC6). CD10 and MUC2, which were markers of intestinal phenotypes, were detected in 13 (48.1%) and 14 (51.9%) of the 27 SSBE cases. Ki-67 LI of SSBE positive cases for CD10 was 23.6 %, while that of SSBE negative cases for CD10 was 14.4 % (p < 0.05). SSBE cases were divided into two groups: one was gastric epithelium type with low Ki-67 LI, and the other was metaplastic epithelium with intestinal metaplasia and high Ki-67 LI. The latter group was suggested to be more important as a premalignant lesion of esophageal adenocarcinoma.