Thirty New Zealand White rabbits were fed diets containing 0 (control), 1, 2, 4, or 8 g cholesterol/kg diet for 12 weeks to determine the cholesterol dosage-response of plasma cholesterol and triglycerides, and the development of atherosclerosis. The concentration of plasma cholesterol increased proportionally with the dietary cholesterol dosage during the first 4 weeks, then remained constant until the $12^{th}$ week. The plasma triglycerides and TBARS concentrations gradually increased with feeding time when rabbits were fed 2 g dosages. Aortas from rabbits fed a 2 g dosage developed moderate to severe multifocal or diffusive atherosclerotic lesions. Aortas from rabbits fed 4 and 8 g dosages were diffusely affected with massive atherosclerotic lesions, and had severe calcification and Alcian blue-positive foci throughout the media of the aorta. These results indicate that at least 2 g of cholesterol/kg in the diet is needed to generate atherosclerotic lesions in rabbit aortas.