Abstract: Objective To investigate the association between a 894 G→T mutation at exon 7 of eNOS gene and diabetic nephropathy in type 2 diabetes mellitus of northern chinese Methods A case control study for 228 chinese subjects (including 143 type 2 diabetes mellitus with or without nephropathy and 85 normal control)was performed The number of the 894 G→T mutation alleles were determined by polymerase chain reaction and restriction fragment length polymorphism(PCR RFLP) method combined by DNA sequencing Results The frequency of the T allele and TG genotype at exon 7 were significantly higher in DN+ group than in DN group and control subjects(P<0 05) Multivariate logistic regression analysis showed that the systolic blood pressure, GHbA1c, TC,TG and the 894 G→T mutation at exon 7 of eNOS gene were risk factors for diabetic nephropathy Conclusion The T allele at exon 7 of eNOS gene are related to diabetic nephropathy in northern chinese type 2 diabetes mellitus The T allele may be a risk factor for development and progression of diabetic nephropathy in chinese subjects