Immunosuppressive regimens with the fewest possible toxic effects are desirable for transplant recipients. This study evaluated the efficacy and relative toxic effects of three immunosuppressive regimens used after kidney transplantation in Kirkuk city. 52 kidney transplanted patients were enrolled in this study and categorized into three treatment groups. The group I patients received standard-dose of CsA, MMF in combinations with prednisolone, and the group II patients received low-dose CsA, Aza in combinations with prednisolone, while the group III patients received low-dose Tac, MMF in combinations with prednisolone. The primary efficacy end point was the renal function; secondary end points were incidence of serious adverse effects and the complication of immunosuppression therapy in transplanted recipient. The mean calculated serum urea and serum creatinine during study were significantly lower in patients receiving low-dose tacrolimus (4.26mmol/L, 112.01μmol/L for urea and creatinine respectively) than in patients receiving standard-dose cyclosporine (6.28 mmol/L, 133.57μmol/L for urea and creatinine respectively). The mean calculated creatinine clearance was significantly higher in patients receiving low-dose tacrolimus (88.50 ml/min) than in patients receiving standard-dose cyclosporine (73.26 ml/min). Whereas there were no significant differences in serum creatinine and creatinine clearance in patients receiving group III (low-dose tacrolimus) and those receiving group II (low-dose cyclosporine). The serum total cholesterol and serum triglyceride concentrations were significantly lower in the group III (low-dose tacrolimus) than in the other two groups. The serum total bilirubin and bilirubin indirect concentrations were significantly elevated in both group I & II receiving patients, while in the group III (low-dose tacrolimus) receiving patients there were no significant changes in serum bilirubin and hepatocellular enzyme. Neither group I (standard-dos