Abstract: Objective To find out the relations between type 2 diabetes mellitus and active cytomeg alovirus(CMV)infection.Methods HCMV DNA and CMV-IgM in sera from 47 type 2 diabetic patients were respectively detected by polymerase reaction (PCR)and ELISA.Patients with positive CMV DNA and(or) CMV-IgM was diag nosed as active CMV infection.Results There was a high correlation between PCR and ELISA in determining HCMV infection(P<0.001).The active CMV infection rate of type 2 diabetic patients was significantly higher than that of the controls(P<0.01),and 72% patients with active CMV infection had a course of disease more than 6 months.The active CMV infection rate of type 2 diabetic patients with higher blood sugar was much higher than that of those with lower blood sugar (P<0.05).Conclusion There existed a hig her re-infection of CMN in type 2 diabetic patients,which was possibly related to the pathog enesis of type 2 diabetes mellitus.