Cyclosporine (CsA) microemulsion has been the mainstay immunosuppressive agent for renal transplant recipients for years. A single daily dosing of cyclosporine (SD) is rarely used. The objective of this study was to evaluate the efficacy of SD versus twice daily dosing of CsA. Retrospective evaluation of SD use was conducted for 44 renal transplant recipients for 12 months (study group). Equal numbers of matched recipients were selected for age, sex, HLA mismatch, donor type, and immunosuppressive regimen (control group). We measured CsA trough (C0) and peak (C2) blood levels, 12-hour CsA profile, and the area under the concentration-time curve (AUC). There were significant differences in C0, C2, and calculated AUC after shifting to SD. In the study group, the mean AUC was 4619 ng/mL/h before versus 6567 ng/mL/h after shifting to SD (P=.004). This became more therapeutic and identical to the mean AUC in the control group, which was 6551 ng/mL/h. Total daily CsA dose was significantly lower in the study group compared with the control group (P<.0001). A significantly higher incidence of hepatitis was observed among the study group (P=.011). There were significantly fewer adverse effects in patients in the study group than the control group. There were no significant differences in graft and patient outcomes between the groups. We concluded that CsA dose should be individualized in renal transplant recipients especially if they have viral hepatitis. SD has the advantage of decreasing dosage and CsA-related adverse effects while maintaining optimal graft function.