The present study was designed to examine whether Yukmijihwang-tang (YJT), which is a Korean decoction for the treatment of renal disease, has an effect on renal functional parameters in association with the expression of aquaporin 2 (AQP 2), Na,K-ATPase, heme oxygenase-1 (HO-1) in rats with ischemia/reperfusion-induced acute renal failure (ARF). Polyuria caused by down-regulation of renal AQP 2 in the ischemia/reperfusion-induced ARF rats was markedly restored by administration of YJT (100 or 200 mg/kg, p.o.) with restoring expression of AQP 2 in the kidney. The expressions of Na,K-ATPase alpha1 and beta1 subunits in the renal medulla and cortex of the ARF rats were also restored in them by the administration of YJT. Administration of YJT lowered the expression of renal HO-1, which was up-regulated in rats with ischemia/reperfusion-induced ARF. The renal functional parameters including creatinine clearance, urinary sodium excretion, urinary osmolality, and solute-free reabsorption were also markedly restored in ischemia-ARF rats by administration of YJT. Histological study also showed that renal damages in the ARF rats were abrogated by administration of YJT. Taken together, these data indicate that YJT ameliorates renal defects in rats with ischemia/reperfusion-induced ARF.