Current immunosuppressive therapies are very effective in preventing acute rejection (AR) and graft loss following renal transplantation. Newer agents now make it possible to develop equally efficacious but better tolerated and less toxic strategies. We compared the efficacy of early low-dose versus high-dose CSA induction therapy in living donor renal transplantation. METHODS: In this clinical trial single-centre study, 90 consecutive recipients of living donor kidney transplants (between November 2002 to October 2003) 51 was female, mean age 48.23 years, were treated either with CSA 5 mg/kg/day plus mycophenolat mofetil (MMF) 30mg/kg/day and prednisolone 1mg/kg/d (group 1, n=42); or CSA 8 mg/kg/day plus MMF 30mg/kg/day and prednisolone 1mg/kg/d/ay (group 2, n=48). Two groups were matched in respect to age, sex, underlying renal diseases, pretransplantation dialysis period, number of transplantation and panel reactive antibody test. CSA dose tapering was initiated in two groups 3 months after transplantation and at the end of first year CSA dose was 3.5±0.65 mg/kg in group 1 and 3.4±0.34 mg/kg in group 2. prednisolone tapered within first two months and reached to 10 mg/day in all patients. MMF dose remained unchanged. Two groups were compared in respect to acute rejection episodes, patients and graft survival and clinical outcomes within two years after transplantation. There were no significant differences between two groups in respect to Clinical outcomes including two years patient survival (97.62% vs 97.92%; Pv=0.76), two years graft survival (90.48% vs 89.59%; PV =0.82), acute rejection episodes (47.61% vs 52.08%; PV=0.09, length of immediate post surgical hospital stay, number of readmissions, total hospitalization days, post transplantation diabetes mellitus and infectious, cardiovascular, gastrointestinal and hematologic complications. There were more hypertension (67.5% vs 50.23% p=0.007), hypertriglyceridemia ( 45.5% vs 32.64% p=0.005), and elevated liver enzymes (12.5% versus 7.14% p=0.018) in group 2 Compared with 8 mg/kg CSA induction therapy the early low-dose CSA is effective, well tolerated and safe with relatively lower side effects.