Abstract: Objective To study the distribution of variable number of tandem repeats (VNTR)polymorphism of ecNOS (endothelial constitutive nitric oxide synthase) gene in Kunming Han Chinese subjects with type 2 diabetes mellitus and to investigate the correlation of the polymorphism of ecNOS with intima-media thickness(IMT). Methods Clinical indicators of unrelated Kunming Han Chinese subjects with type 2 diabetes (n=143)and healthy control(n=80) were investigated, and the genotypes of ecNOS were assessed by PCR.The IMT, which can be used to estimate early stages of artherosclerosis, was measured by high-resolution ultrasonography. Results Allele frequency of the 4a was 0.084 in Kunming Han Chinese subjects.Serum triglyceride level was significantly higher in subjects with 4a allele, and the IMT values did not show any significant difference among patients with various ecNOS genotypes. Conclusions The ecNOS 4a allele is correlated with serum triglyceride level but not with IMT value