The effects of a protein-restricted diet on renal recovery following renal ischemia were studied. The renal function was assessed by measuring the inulin clearance (CiN), the p-aminohippurate clearance (CPAH), and the percent fractional sodium excretion (%FENa) 24 h after 45 min renal ischemia. In rats fed with a regular diet (containing 19.6% protein), ClNwas 10.0±2.2üL/min/100 g body weight (BW), CPAH0.08±0.02 mL/min/100 g BW, and %FENa14.8±2.0, 24 h after renal ischemia. In contrast, feeding rats with a no-protein diet (0% protein) for 1 week prior to the ischemic insult significantly improved renal recovery (CIN48.0±9.3ü/min/100g BW, CPAH0.16±0.04mL/min/100 g BW, and %FENa2.43±0.58). Feeding rats with a no-protein diet for 3 weeks prior to ischemic insult further improved the renal recovery (ClN113±30üL/min/100 g BW, CPAH0.47±0.17 mL/min/100 g BW, and %FENa1.55±0.29). When rats fed with a regular diet were exposed to 45 min of ischemia, the survival rate on day 7 was 16.7%. In rats fed with the no-protein diet for 1 week and for 3 weeks, the 7-day survival rate was 100% in each case. The survival rate of rats fed for 3 days instead of 7 days with the no-protein diet was 87.5%. When a no-protein feeding was shortened to 1 day, no beneficial effects were observed and survival rate was 14.3%. When the ischemia time was prolonged to 60 min and 75 min, the 7-day survival rate with the regular diet was 0%, while the rates for the no-protein diet for 1 week were still 100%. Even after 90 min of ischemia, the 7-day survival rate for rats with the no-protein diet was 60%. These results clearly demonstrate the beneficial effects of protein-restricted diet against postischemic acute renal failure.