Background Calpain-10(CAPN10)has been identified as a susceptibility gene in type 2 diabetes mellitus (T2DM) and insulin resistance.The present study aimed to identify the effects of genetic variations in the CAPN10 gene on the development of type 2 diabetes and hypertension in north Han Chinese population.Methods We performed a case-control study and genotyped single nucleotide polymorphism(SNP)-44,-43,-19 and -63 of CAPN10 gene in 1046 subjects from the north China,including 493 patients with T2DM and hypertension and 553 age-and gender-matched normal healthy controls.Results Univariate analysis showed that the four polymorphisms were not independently associated with T2DM and hypertension.However,the frequency distributions of SNP-44 allele C(allele 2)(17.89% vs 9.80%,P=0.0016)and genotype CC(22)(4.21% vs 1.01%,P=0.0059)in obese patients(body mass index≥30 kg/m2)were different from those in non-obese patients.Logistic regression analyses revealed that carriers of lhe 1112/1221 diplotype had a significantly lower odds ratio for diabetes and hypertension(OR=0.399,95% CI,0.196-0.814,P=0.0115).The 1112/1121 diplotype associated with significantly increased risk of type 2 diabetes in Mexican-American was not associated with the increased risk in Chinese.Conclusion These results suggested that CAPN10 gene variations might play roles in the risk of diabetes and hypertension in north Han Chinese population.