PURPOSE:Enhanced immunosuppression for preventing acute rejection, But infection is an inevitable complication. This study was performed to evaluate the risk factors of herpes simplex virus (HSV) and varicella zoster virus (VZV) infection which are frequent and serious complication of renal transplant recipients. METHOD:We evaluated the incidence and risk factors for post-transplant HSV and VZV infection in three hundred and twenty three adult renal transplant recipients. RESULTS:The averaged period of infection was 37.8 months and 42% of infection occurred within six month after transplantation. Prevalence of HSV and VZV infection in diabetes patients are higher than that of non-diabetes patients (p=0.01). The other factors such as age, sex, acute rejection and immunosuppressive regimens, antibody induction didnt affect HSV and VZV infections in renal transplant recipients. CONCLUSION:As diabetic condition suggested more susceptibility to HSV and VZV infections, it is necessary to evaluate the possible occurrence of HSV and VZV infections carefully in transplant recipients with diabetes.