Weanling rats were fed atherogenic diets containing 2% cholesterol and 0.5% bile acids for 4 weeks. The experimental diets contained 10% protein derived from soy protein, wheat gluten, or wheat gluten supplemented with lysine and threonine. The control diet contained 10% protein derived from casein. Rats fed the plant proteins were found to have lower serum cholesterol and triglyceride levels, no detectable amounts of low density lipoprotein, a smaller amount of very low density lipoprotein and a higher concentration of high density lipoprotein (HDL) as compared to the control animals. There were no differences in the serum HDL-cholesterol level between the control and the experimental groups. It was shown that the hypocholesterolemic effect of wheat gluten is independent of the low lysine concentration or the ratio of lysine/arginine in it.