Introduction: Epstein-Barr virus (EBV) and herpes simplex virus infection are common in general population. Nevertheless, transplant candidates with EBV and/or HSV seronegative who received kidney from donor with seropositive had increased risk for primary infection. Primary EBV infection can cause post-transplant lymphoproliferative disease while primary HSV infection can lead to disseminated infection. Current guideline recommended pre-transplant screening with EBV IgG and HSV IgG, however cost of such routine testing is relatively high in our country. Data regarding of seroprevalence of EBV and HSV in Thai kidney transplant (KT) patients is lacking. Methods: A retrospective cohort study in all patients who had underwent KT in Siriraj Hospital between 1st January 2014 and 31st December 2019 was conducted. EBV IgG and HSV IgG in kidney transplant recipients were tested when the patients were admitted for KT. The patients without EBV and HSV IgG results were excluded. Seroprevalence of HSV and EBV and risk factors for seronegative were analyzed. Results: Of 445 patients, all patients had EBV IgG results while 418 patients (93.9%) had HSV IgG results. EBV seronegative was revealed in 5 patients (1.1%). Mean age of patients with EBV seronegative was significantly less than seropositive patients (22.4 ± 15.5 vs 42.1 ± 12.7 years; p = 0.001). Age of EBV seronegative patients were 12, 13, 15, 23 and 49 years, respectively. HSV seronegative was found in 121 patients (27.2%) with median age of 39 (12 – 62) years. Patients without previous HSV exposure were significantly younger than seropositive ones (39.0 ± 11.7 vs 45.4 ± 10.4; p < 0.001). Conclusion: Almost Thai KT patients had previous EBV exposure, thus pretransplant EBV screening is not necessary especially in adult KT recipients. Negative HSV IgG was found in three fourth of KT patients. HSV screening might be beneficial for post KT prophylaxis.