It is proposed that atherosclerosis is a chronic inflammatory disease in which monocyte-derived macrophages are doing harm and smooth muscle cells are essentially reparative. Activities of macrophages that might be contributory to the development of atherosclerosis are tabulated. Observations and experiments are described that suggest macrophages may be contributing to lipoprotein oxidation within the plaque and that individual humans vary in their macrophage oxidative capacity. The possibility of intervention with antioxidants is discussed.