The purpose of this study was to investigate the effect of iloprost, a cytoprotective prostacyclin analog, on renal injury during unilateral renal I/R in rats and to determine whether the levels of serum cystatin C (CyC) and beta2-microglobulin (B2M), as markers of glomerular function, might denote this injury. Thirty-two Wistar rats were randomized into four groups (n = 8) as follows: control (sham laparotomy), renal I/R (60-min left renal ischemia and 120-min reperfusion), renal I/R + iloprost (20 ng kg(-1) min(-1) infusion during renal I/R period, i.v.), and control + iloprost. Blood and kidney tissue samples were obtained for biochemical and histological analysis from all rats. Serum urea, creatinine, CyC, and B2M levels were evaluated for biochemical analysis. Histopathological changes in renal structure were examined for histological analysis. Serum urea, creatinine, and CyC levels were significantly increased in the renal I/R group. Iloprost treatment decreased these three markers in the renal I/R + iloprost group. beta2-Microglobulin levels were not significantly changed in any group. Histological analyses showed that renal I/R elicited significant renal injury, whereas iloprost significantly decreased I/R-induced renal injury. Serum CyC level is one of the good indicators of acute renal damage due to I/R produced by renal artery occlusion. In contrast, we have shown that there are no significant changes in the levels of serum B2M levels that would make it an accurate diagnostic tool for detecting acute changes in renal injury subject to renal I/R in rats.