BACKGROUND Endometrial cancer is one of the most common cancers in female patients. Many studies have investigated the association between the MDM2 T309G genotype and endometrial cancer incidence, but the results have been inconclusive. MATERIAL AND METHODS We performed a systematic search in PubMed and Web of Science databases (update until October 21, 2015) for all English-language publications. The associations are indicated as pooled odds ratio (OR) and 95% confidence intervals (CI). RESULTS We identified 8 relevant publications (9 case-control studies), including 2188 cases and 4654 controls, that assessed the relationship between MDM2 T309G polymorphism and endometrial cancer risk. There was a significant association between MDM2 T309G polymorphism and endometrial cancer risk in the overall population in the recessive model (OR=1.61; 95% CI: 1.19-2.19; P=0.002). In the subgroup of different ethnic populations, the subgroup analysis showed MDM2 T309G polymorphism was significantly associated with increased endometrial cancer risk in Caucasians (OR=1.75; 95% CI: 1.16-2.63; P=0.007). No similar result was found in Asians. CONCLUSIONS Our meta-analysis provides evidence that MDM2 T309G polymorphism is associated with endometrial cancer, especially in Caucasians.