Alfalfa (Medicago sativa) is a leguminous plant with high contents of phytoestrogen and saponin which are both useful in preventing cardiovascular disorders. This study was designed to evaluate the preventive effect of dietary alfalfa on the development and the progression of atherosclerosis in hyperlipidemic rabbits. Twenty male rabbits were obtained and kept under standard conditions. After 2 weeks of accommodation to the new place, the animals were semi-randomly distributed into four groups of five each. Animals in Group 1 received basic diet and the ones in Group 2 received the same diet to which 1% cholesterol was added. Groups 3 and 4 received similar diets as Groups 1 and 2 respectively, but supplemented with alfalfa. Each of the four groups was fed with its respected diet for a period of 12 weeks. Fasting blood samples were collected from all animals at the beginning and at the end of the study and blood factors were measured. At the end of the study samples from the right and the left coronary arteries as well as the aorta were collected from all animals for pathological evaluations. Though dietary alfalfa decreased total cholesterol, LDL and triglyceride and this effect was not significant, but dietary alfalfa significantly increased HDL. The formation of fatty streaks in the aorta, the right and the left coronary arteries were significantly reduced under the influence of dietary alfalfa. The indication that dietary alfalfa may have preventive effects on the progression of fatty streak formation calls for more studies to clarify the mechanisms of the effect.