KCNQ1 has been identified as a susceptibility gene of type 2 diabetes mellitus(T2DM) in Asian populations through genome-wide association studies. However, studies on the association between gene polymorphism of KCNQ1 and T2 DM complications remain unclear. To further analyze the association between different alleles at the single nucleotide polymorphism(SNP) rs2237892 within KCNQ1 and TD2 M and its complications, we conducted a case-control study in a Chinese Han population. The C allele of rs2237892 variant contributed to susceptibility to T2DM(odds ratio [OR], 1.45; 95% confidence interval [CI], 1.20–1.75). Genotypes CT(OR, 1.97; 95% CI,1.24–3.15) and CC(OR, 2.49; 95% CI, 1.57–3.95) were associated with an increased risk of T2 DM. Multivariate regression analysis was performed with adjustment of age, gender, and body mass index. We found that systolic blood pressure(P = 0.015), prevalence of hypertension(P = 0.037), and risk of macrovascular disease(OR, 2.10; CI, 1.00–4.45) were significantly higher in subjects with the CC genotype than in the combined population with genotype either CT or KCNQ1 has been identified as a susceptibility gene of type 2 diabetes mellitus (T2DM) in Asian populations through genome-wide association studies. However, studies on the association between gene polymorphism of KCNQ1 and T2 DM cells remain unclear. To further analyze the association between different alleles at the single nucleotide polymorphism (SNP) rs2237892 within KCNQ1 and TD2 M and its complications, we conducted a case-control study in a Chinese Han population. The C allele of rs2237892 variant contributed to T2DM (odds ratio [OR] , 1.45; 95% confidence interval [CI], 1.20-1.75). Genotypes CT (OR, 1.97; 95% CI, 1.24-3.15) and CC (OR, 2.49; 95% CI, 1.57-3.95) were associated with an increased risk of T2 DM. Multivariate regression analysis was performed with adjustment of age, gender, and body mass index. We found that systolic blood pressure (P = 0.015), prevalence of hypertension (P = 0.037) OR, 2.10; CI, 1.00-4.45) were significantly higher in subjects with the CC genotype than in the combined population with genotype either CT or