Renal transplant recipients receive immunosuppressive therapy to prevent acute rejection. However, immunosuppressive drugs are known to cause opportunistic infectious diseases. An ATP monitoring assay on the peripheral CD4⁺ lymphocytes is useful for evaluating the risks of rejection and infection episodes in transplant recipients. The graft survival rate of cadaveric-donor renal transplant recipients has been reported to be lower than that of living-donor renal transplant recipients. Therefore, we compared the ATP concentrations in the peripheral lymphocytes of living-donor and cadaveric-donor renal transplant recipients. We measured the ATP concentrations in the peripheral lymphocytes of 17 living-donor and 7 cadaveric-donor renal transplant recipients every week for six weeks, and at three, six, and twelve months after transplantation. The ATP concentrations were measured using an ImmuKnow^® assay kit. The rates of cytomegalovirus (CMV) infection and rejection episodes were also compared. With the exception of the concentrations at three weeks after transplantation, no significant difference was observed in the ATP concentrations of living-donor and cadaveric-donor renal transplant recipients. At three weeks, the ATP concentrations of living-donor recipients were significantly higher than those in the cadaveric-donor recipients (p = 0.024). However, the rates of both CMV infection and rejection episodes in living-donor and cadaveric-donor renal transplant recipients did not differ to a statistically significant extent during the twelve-month study period. Our data suggest that the ATP concentrations in the peripheral lymphocytes of living-donor and cadaveric-donor recipients were similar after renal transplantation (with the exception of the 3-week time-point). These observations suggest that the groups had similar risks of CMV infection and rejection until 12 months after transplantation.