It is reported that the expression level of MLL3 in gastric cancer tissue highly correlates with tumor progression. However, whether MLL3 genetic variants are associated with the risk of gastric cancer remains unclear. In this study, we conducted a genotyping analysis for MLL3 in 314 cases of gastric cancer and 322 controls from the Chinese Han population. 4 SNPs (rs6943984, rs4725443, rs3800836, rs6464211) were selected for the present analysis. We found 2 SNPs (rs6943984, rs4725443) of MLL3 gene were significantly associated with the risk of gastric cancer : the rs6943984 with the minor allele A and rs4725443 with the minor allele C revealed strong associations with increased gastric cancer risk [P < 0.001, OR=1.97, 95% CI=1.48~2.64 and P <0.001, OR=2.23, 95% CI=1.54~3.24]. Haplotype analysis of the four SNPs showed that haplotype A-T-A-C, G-T-G-C, and G-C-A-C increased the risk of gastric cancer (P <0.001, P=0.18, and P<0.001, respectively), while haplotype G-T-A-C significantly reduced the risk of gastric cancer (P <0.001). We concluded that MLL3 variants are significantly associated with gastric cancer risk. Our results for the first time provided new insight into susceptibility factors of MLL3 gene variants in carcinogenesis of gastric cancer of the Chinese Han population.