The cost-effectiveness of each of the six hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors currently available was studied. For a cohort of patients between the ages of 60 and 85 years with coronary heart disease (CHD) who were taking atorvastatin, cerivastatin, fluvastatin, lovastatin, pravastatin, or simvastatin, the number of survivors, the annual direct cost per survivor, and the annual indirect cost saving per survivor associated with the predicted reduction in the rate of nonfatal myocardial infarction recurrences were projected. Percent reductions in excess mortality due to CHD were derived from the relative risks of cardiac mortality in treatment versus control groups in the Scandinavian Simvastatin Survival Study (4S). Doses necessary to provide a long-term 35.57% reduction in low-density- lipoprotein (LDL) cholesterol, as seen in 4S, were estimated. One-way sensitivity analyses were performed to assess the importance of the baseline assumptions. The cost per year of life saved ranged from $5,421 with atorvastatin to $15,073 with lovastatin. The patient's age at time of diagnosis of CHD had a major impact on the cost-effectiveness of the drugs; cost-effectiveness per year of life saved was higher for older patients than younger patients. The six currently marketed HMG-CoA reductase inhibitors varied widely in cost and effectiveness in producing reductions in the LDL-cholesterol concentrations that have been shown to prevent recurrent MI; there was an approximately threefold difference in the cost per year of life saved between the most cost-effective and least cost-effective agents.