1. A dietary intervention study targeting female students by using cake containing soybean protein and isoflavone was conducted. Female students (n = 120) were divided into three Groups (A, 6.26 g of soybean protein and isoflavone at 50 mg/day; B, 1.36 g soybean protein and isoflavone 50 mg; and C, a wheat puff as placebo). Intervention period was 4 weeks. The ratio of hypercholesterol in each group indicated a high value; A: 25%, B: 17.9% and C: 24.4%. 2. Total cholesterol as well as the rate of hypercholesterolemia decreased in Group A. The average total cholesterol significantly reduced (P < 0.001) from 242 +/- 17 to 220 +/- 25 mg/dL in Group A. 3. Dietary intake of soy protein for 4 weeks could be effective in reducing CHD risk among Japanese female students with a high plasma cholesterol level.