Oxygen-free radical reactions have been implicated in many chronic disease processes, including atherosclerotic cardiovascular disease. Recent studies of lipid metabolism have suggested that oxidative modification of low-density lipoprotein accelerates atherogenesis. Micronutrient antioxidants, including alpha-tocopherol and beta-carotene, however, can neutralize oxygen-free radicals and inhibit low-density lipoprotein oxidation. This review examines (1) the role of oxidized low-density lipoprotein in atherogenesis, (2) the association between nutritional antioxidant intake and atherosclerosis, and (3) observational and clinical trial data on the effect of antioxidants in reducing the risk of coronary heart disease. While evidence suggests that antioxidant supplements protect against coronary heart disease, definitive recommendations await results from ongoing randomized trials of primary and secondary prevention.