Dexmedetomidine (dex) is a potent, highly selective and specific alpha 2-adrenoreceptor agonist. This experimental study was designed to investigate protective and therapeutic effect of two different doses of dex, on kidney damage induced by ischemia-reperfusion (I/R) in rats. Male Sprague - Dawley rats were divided into four groups, each including 10 animals: control group, ischemia-reperfusion (I/R) group; treated groups with 10 mu g/kg of dex and 100 mu g/kg of dex. After removing right kidney of the rats, the left kidney has performed ischemia during 40 min and reperfusion in the following 3 h. The histopathological findings, and also tissue superoxide dismutase (SOD) and catalase (CAT) enzyme activity, malondialdehyde (MDA), glutathione (GSH), serum blood urea nitrogen (BUN), creatinine (Cre) and tumor necrosis factor-alpha (TNF-alpha) levels were determined. In the I/R group, compared to the control group, levels of BUN, Cre and kidney tissue MDA have increased significantly, SOD, CAT enzyme activity and glutathione levels have decreased significantly. In the dex10 group, compared to the I/R group, levels of Cre and TNF-alpha have decreased significantly, while the SOD activity has increased significantly. In the dex100 group, compared to the I/R group, levels of BUN, Cre have decreased significantly, while the SOD activity has increased significantly. In the I/R group, there was also extensive tubular necrosis, glomerular damage in the histological evaluation. Dex ameliorated these histological damages in different amounts in two treatment groups. In this study, the protective effects of dex against renal I/R injury have been evaluated by two different amount of doses.