Aim To observe the effects of L-arginine on athersclerosis and serum lipids in rabbits. Methods Forty-five rabbits were divided into three groups accidentally. Normal group received nornal chow, control group received 2.5% cholesterol and normal drink, treatment group received 2.5% cholesterol and 2.25% L-arginine solution for 7 or 14 weeks. The levels of serum total cholesterol (TC) and triglycerides (TG) were investigated, while atherosclerosis was measured by image pattern analysis method after ascending aorta and descending aorta were stained with Oil-Red-O. Results The serum total cholesterol and triglycerides had significantly inhibitted by treatment with L-arginine at 7 weeks.But there was no significant difference between treatment with and without L-arginine at 14 weeks. Similar results of atherosclerosis was seen in ascending aorta. But at 7 or 14 weeks, atherosclerosis was less in descending aorta of arginine fed animals than that of rabbits fed cholesterol only. Conclusion The results suggest that chronic dietary L-arginine suppllemintation does not result in a sustained limitation in atherosclerosis and decrease in serum lipids.