ObjectiveTo systematically review the expression and clinical significance of CD133 in gastric cancer. MethodsSearches in the databases such as PubMed, EMbase, Web of Knowledge, The Cochrane Library (Issue 10, 2013), CBM, VIP, CNKI and WanFang Data were performed to collect case-control studies about the association between the CD133 expression and gastric cancer up to October 2013. Two reviewers independently screened the literature according to the inclusion and exclusion criteria, extracted the data, and assessed the methodological quality of the included studies, and then RevMan 5.2 software was used for meta-analysis. ResultsNine case-control studies involving 623 patients were included. The results of the meta-analyses showed that, there were significant differences of CD133 expression in the following comparisons:gastric cancer tissues vs. normal esophageal tissues (OR=3.89, 95%CI 1.87 to 8.11, P=0.000 3), lymph node metastasis vs. non-lymph node metastasis (OR=2.75, 95%CI 1.99 to 3.81, P < 0.000 01), clinical stages Ⅲ-Ⅳ vs. clinical stages Ⅰ-Ⅱ (OR=2.83, 95%CI 2.13 to 3.76, P < 0.000 01), as well as distant metastasis vs. non-distant metastasis (OR=2.38, 95%CI 1.47 to 3.85, P=0.000 4). While no significant difference was found between the cell differentiation G1-G2 vs. cell differentiation G3 (OR=1.70, 95%CI 0.90 to 3.21, P=0.10). ConclusionOver-expression of CD133 is associated with lymph node metastasis, distant metastasis and poor TNM stage, which suggests that CD133 may participate in the carcinogenesis of gastric cancer. However, due to the limitations of the included studies, more large-sample high-quality case-control studies are still needed to verify these results.