Potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11) E23K gene polymorphism has been indicated as relevant to type 2 diabetes mellitus (T2D) susceptibility, but research results remain debatable.To investigate the relationship between KCNJ11 E23K gene polymorphism and T2D in the Chinese Han population, a meta-analysis involving 3,080 T2D patients and 3,029 controls from five separate studies was conducted. The pooled odds ratio (ORs) for the association between KCNJ11 E23K gene polymorphism and T2D and its corresponding 95 % confidence interval (95 % CI) were estimated using a random effects model.A significant association was observed between the KCNJ11 E23K gene polymorphism and T2D in the pooled Chinese Han population through an allelic genetic model (OR: 1.21, 95 % CI: 1.04-1.40, P = 0.01) and a recessive genetic model (OR: 1.44, 95 % CI: 1.25-1.65, P < 0.00001). In contrast, no significant association was observed between the KCNJ11 E23K gene polymorphism and T2D in the dominant genetic model (OR: 0.66, 95 % CI: 0.41-1.07, P = 0.09).The KCNJ11 E23K gene polymorphism is associated with T2D risk in the Chinese Han population.