Our meta-analysis results indicated that KCNQ1 rs2237892 polymorphism could be correlated with the risk of type 2 diabetes mellitus under the C allelic, recessive, and dominant genetic models (OR = 1.25, 95% 1.19–1.32, p < 0.001; OR = 1.50, 95% CI 1.34–1.68, p < 0.001; OR = 1.26, 95% CI 1.14–1.40, p < 0.001, respectively). The gene discussed is KCNQ1; the disease is type 2 diabetes mellitus.