Background: Co-administration of diltiazem and cyclosporine A (CsA) in kidney transplant recipients shows improvement of renal transplantation outcomes. Methods: We respectively analyzed 1531 kidney transplant recipients treated by different immunosuppressive therapy schemes from 1986 to 2003. They were divided into three groups depending on their immunosuppressive therapy schemes: control group with a standard triple therapy without use of diltiazem; study group I with the combination of diltiazem and the standard triple therapy but slightly low CsA; study group II with combination of diltiazem and a modified standard triple therapy but lower CsA. The CsA blood concentrations, posttransplant complications, and long-term survival in the three groups were compared. Results: The results showed that the patient and allograft survival in the study group II was 69.9 and 65.1%, respectively, significantly higher than that in the control group (50.7 and 47.6%). Occurrence of hepatotoxicity and nephrotoxicity episodes was higher in the control group than those in the study group I and the study group II. The incidence of acute rejection in the control group was 30.3% (23/76), similar to 28.0% (184/657) in study group I, but statistically significantly higher than 7.6% (61/798) in the study group II. Conclusion: Combination of diltiazem and CsA in the kidney allograft recipients tends to reduce the CsA oral dosage, improve patient survival, and decrease the occurrence of hepatotoxicity and nephrotoxicity.