Chronic rejection is the most prevalent cause of renal transplant failure in the late post-transplant period. The clinical significance of acute rejection episodes on occurrence of chronic rejection is controversial. We analyzed 503 cases of the first renal transplantation maintained by calcinurine inhibitor for the correlation of acute rejection and clinical chronic rejection. The later the first episode of acute rejection occurred, the shorter was the half-life of graft. The acute rejection occurring within 3 post-transplant months worsens long-term graft survival if the peak creatinine level exceeds 2 mg/dl. Multivariate analysis by the Cox proportional hazard model for factors affecting cadaver graft loss by chronic rejection, revealed that the risk factor of acute early rejection was lower than those of donor age and post-transplant hypertension.