Deposition of cholesterol esters in the arterial intima is a characteristic feature of human atherosclerosis. Very little is known about the mechanisms by which cells normally regulate their cholesterol ester content. Recent studies in cultured human cells demonstrate the existence of a cell surface receptor that binds plasma low density lipoproteins and regulates the sterol content of cells by modulating the rates of uptake, esterification, and synthesis of cholesterol. A possible role for this lipoprotein receptor in the pathogenesis of atherosclerosis is discussed.