Cyclosporine A (CsA) is shown to improve the long-term survival after organ transplantations. However, CsA therapy is associated with a variety of side effects, in which the nephropathy is the major one. Recent studies have suggested an increased oxidative stress as a possible leading cause of the drug nephrotoxicity. Therefore, this study was designed to evaluate CsA administration effects on the oxidative stress status of the kidney tissue. Adult male Sprague-Dawley rats were randomly assigned in two groups. One group received CsA (ip, 25 mg/kg/day, for two weeks) and a control group without CsA administration was included. After two weeks, kidneys of the rats from both groups removed under anesthesia. 50 mg fresh samples of the kidney tissues were homogenized in the ice cold phosphate buffer. Total antioxidant capacity (ferric reducing/antioxidant power; FRAP) in the homogenates were assayed based on Benzie spectrophotometric method. FRAP in the kidney tissues had been significantly decreased by two weeks of CsA administrations when compared to the control rats (p<0.05). These data suggest that CsA administration may decrease antioxidant capacity of the renal tissues. More studies on the evaluation of the protective effects of antioxidant therapy against CsA nephrotoxicity remain to be down.