To assess the cost-effectiveness of cholesterol-reducing therapy with cholestyramine and simvastatin in the primary prevention of coronary artery disease in The Netherlands, a model of coronary artery disease incidence was used based on multivariate logistic risk functions from the Framingham study. For men with initial cholesterol levels of 8 mmol/liter, the cost per year of life saved of cholestyramine, expressed in Dutch guilders (NLG; 1 NLG = $0.50), ranges from approximately NLG 208,000 to NLG 483,000, depending on the patient's age at initiation of therapy. For simvastatin, cost-effectiveness ranges from NLG 46,000 to NLG 98,000 per year of life saved among this group of men. Similar differences between simvastatin and cholestyramine therapy prevail among women, although the costs per year of life saved for both agents are considerably higher. These results suggest that (1) simvastatin is substantially more cost effective than is cholestyramine; (2) simvastatin therapy compares favorably with other generally accepted medical practices, especially if treatment is initiated at an early age; and (3) as its long-term safety record becomes more established, simvastatin may become accepted as a drug of first choice in the treatment of persons with elevated serum cholesterol levels.