Several authors reported that vegetable proteins cause to decrease serum cholesterol and reported the effect of limiting amino acid balance in dietary protein on the blood component. This study was designed to observe growth rate and blood component in 1% cholesterol-fed male rats intake pure isolated soy proteins and methionine for 4 weeks. The diets were supplemented with either 20% casein or isolated soy protein as dietary protein sources and methionine as limiting amino acid of isolated soy protein and casein protein. The results were as follows; 1) The body weight gain was the greatest in casein groups. 2) Serum total cholesterol concentration was significantly increased by casein groups and slightly decreased by isolated soy protein groups. 3) Serum HDL-cholesterol concentration was significantly increased by isolated soy protein groups than control group. 4) Serum total lipid and triglyceride concentrations were significantly decreased by isolated soy protein groups than control group. 5) Serum glucose concentration was significantly increased by isolated soy protein plus 0.8% methionine than control group. 6) Serum total protein and albumin concentrations were significantly increased by all experimental diets groups than control group. Especially, casein groups were the most increased in all experimental diets groups.