The results of recent large, prospective clinical trials have established that the reduction of plasma total and low density lipoprotein cholesterol concentrations in certain hyperlipidemic patients reduced their risk for developing symptomatic cardiovascular disease. Attention has now been turned to both defining which individuals should be treated and how best to treat those patients. Utilizing the concepts of human lipid, lipoprotein, and apolipoprotein metabolism that have evolved over the past 20 years, the metabolism of the plasma lipoproteins can be effectively modulated in the majority of hyperlipoproteinemic patients. In addition to summarizing human lipoprotein metabolism, this article outlines a step-by-step approach to the treatment of hyperlipoproteinemia.