We previously demonstrated that several clinically utilized volatile anesthetics including sevoflurane protected against renal ischemia reperfusion (IR) injury by reducing necrosis and inflammation in vivo. We also demonstrated that volatile anesthetics produced direct anti-necrotic and anti-inflammatory effects in cultured renal tubules via mechanisms involving the externalization of phosphatidylserine and subsequent release of TGF-1. In this study, we tested the hypothesis that volatile anesthetic-mediated renal protection requires TGF-1 and SMAD3 signaling in vivo. We subjected TGF-1+/+, TGF-1+/-, SMAD3+/+ or SMAD3-/- mice to renal IR under anesthesia with pentobarbital or with sevoflurane. Although TGF-1+/+ and SMAD3+/+ mice were significantly protected against renal IR injury under sevoflurane anesthesia with reduced necrosis and inflammation, TGF-1+/- mice and SMAD3-/- mice were not protected against renal IR with sevoflurane. Furthermore, a neutralizing TGF-1 antibody blocked renal protection with sevoflurane in TGF-1+/+ mice. Sevoflurane caused nuclear translocation of SMAD3 and reduced the TNF- induced nuclear translocation of NFkB in primary cultures of proximal tubules from TGF-1+/+ but not in TGF-1+/- mice. Finally, sevoflurane protected against necrosis induced with hydrogen peroxide in primary cultures of proximal tubules from TGF-1+/+ mice or SMAD3+/+ mice but not in proximal tubules from TGF-1+/- or SMAD3-/- mice. Therefore, we demonstrate in this study that sevoflurane-mediated renal protection in vivo requires the TGF-1SMAD3 signaling pathway.