Renal ischemia/reperfusion (I/R) injury is one of the main causes of postoperative renal failure. Activated neutrophils are implicated in the development of I/R-induced renal failure. JTE-607 has been reported to be a potent inhibitor of the multiple inflammatory cytokines in the endotoxic shock mouse model and heart Langendorff perfusion model. In this study, we examined whether JTE-607 attenuates I/R-induced renal injury by reducing neutrophil activation. Male wistar rats were intravenously administered JTE-607 (JTE group, 30 mg/kg) or 5% mannitol (control group) 30 min before ischemia. JTE-607 reduced the I/R-induced increases in the serum concentrations of blood urea nitrogen and creatinine, and improved the histopathologic changes, including acute tubular necrosis. I/R-induced an increase in neutrophil activation, reflected by increases in renal cytokine-induced neutrophil chemoattractant (CINC)-1 and myeloperoxidase (MPO) concentrations which were significantly reduced by JTE-607. These findings indicate that JTE-607 attenuates I/R-induced acute renal injury, probably by inhibiting neutrophil activation. JTE-607 might be a novel therapeutic strategy for the protection of postoperative renal failure in surgery associated with renal ischemia as well as renal transplantation.