Background: As a negative regulator of P53, MDM2 plays an important role in carcinogenesis; a polymorphism in its promoter region. SNP309 T>G, is known to increase the expression of MDM2, thus being considered related to higher susceptibility to neoplasia. However, no agreement has been achieved regarding its effects on gastric cancer. Methods: The present systematic meta-analysis was performed based on comprehensive literature search from Pubmed, Web of science and CBM databases. Results: It was suggested from 6 independent studies that the GG genotype is associated with a significantly increased risk of gastric cancer (Recessive: OR = 1.43, 95% CI = 1.08-1.91, P = 0.013), and subgroup analysis also confirmed the relationship (English publications-recessive model: OR = 1.45, 95% CI = 1.10-1.91, P = 0.009; Studies in China-recessive model: OR = 1.58, 95% CI = 1.08-2.30, P = 0.017). No publication bias was detected. Conclusion: The meta-analysis indicated a significant inverse association between GG genotype carriage and elevated risk of gastric cancer. However, more studies and detailed information are needed to fully address the topic.