Objectives: Cytomegalovirus (CMV) or BK virus (BKV) infection is one of the important opportunistic infections in kidney transplant recipients (KTRs). CMV or BKV infection can affect the early or late clinical outcome in KTRs, but the clinical impacts of two infections are not clear. Methods: We investigated 205 patients who performed kidney transplantation (KT) at Keimyung University Dongsan Hospital between 2014 and 2019. We divided KTRs into four groups: no infection (G1), CMV infection (G2), BKV infection (G3), and coinfection (G4) groups. We investigated the incidence of de novo donor specific-antibody (DSA) and biopsy-proven acute rejection (BPAR), allograft function after KT, and graft and patient survivals. Results: There were no significant differences in the age, gender, dialysis vintage, HLA mismatches, KT type, immunosuppressant and preformed DSA among them. However, the incidence of de novo DSA in G3 was significantly higher than other groups (62.5% vs. 21.2%; 12.8%; 0%, P=0.009). Mean eGFR in G4 at discharge, 1 year and 3 year after KT was the lowest significantly compared to other groups. The rate of BPAR within 1 year after KT was significantly higher in G4 compared to other groups (50% vs. 5.7%, 10%, 25%, P=0.038). The rates of BPAR since 1 year after KT tended to be higher in G4 compared to other groups (50%, vs. 3.4%, 4.4%, 16.7%, P=0.091). There were no significant differences in the death-censored graft survival rate and patient survival rate among them. Conclusions: Although CMV or BKV infection did not increase graft failure and mortality in our study, it caused to poor allograft function and the development of BPAR at the early period after KT. Therefore, control of adequate immunosuppressant is needed to prevent the development of CMV and BKV coinfection at the early period after KT.