The effects of diet induced hyperlipidemia on kidney function were studied in Sprague-Dawley rats fed high fat diet containing 20% beef tallow and high cholesterol diet containing 5% cholesterol for 8, 12, 16 weeks, respectively. The concentrations of serum total lipid, total cholesterol and LDL-cholesterol were significantly high cholesterol diet groups during all experimental periods (p<0.05). HDL-cholesterol concentration was the lowest value in high cholesterol diet group of 16 weeks(p<0.05). Triglyceride concentration was not affected by experimental diets. Serum total protein, albumin and creatinine concentration tended to higher in high cholesterol diet groups than those in high fat diet groups. And serum urea-N concentration was higher in high fat diet group of 16 weeks than that in other diet groups. Urinary total protein and urea-N were higher in high cholesterol diet groups than those in other diet groups regardless of experimental period period. There was no significant difference in urinary creatinine concentratin among diet groups(p<0.05). GFR was lower in high cholesterol diet groups than that in high fat diet groups at 8, 16 weeks, respectively. Wet weight per body weight, total lipid, triglyceride, total cholesterol concentations of liver tissue were apparently high in high cholesterol diet groups(p<0.05). Kidney wet weight per body weight wer not affected by experimently diets, total lipid concentration of kidney tissue was significantly high in high fat diet groups of 12 weeks(p<0.05), kidney tissue triglyceride concentrations of high cholesterol diet groups of 12, 16 weeks apparently low, and total cholesterol concentration of kidney tissue was higher in experimental diet groups than that of control groups at 12, 16 weeks(p<0.05). Fecal excretion, total lipid, triglyceride and cholesterol concentrations of feces were markedly high in all high cholesterol diet groups except high fat diet group of 16 weeks. The results of light microscopic examination indicated that glomerulosclerosis was not obsrved in rats fed experimental diets.