Assessments were made of: effects of treatment on health outcomes (symptomatic coronary heart disease, death from coronary heart disease, and mortality from all causes); costs and effectiveness of specific dietary and pharmacological interventions; effects of delays in instituting treatment; effects of changing the interval between blood cholesterol tests on the probability and duration of treatment delay; cost and health consequences of modifying screening and treatment recommendations for other risk factors, age, and gender; population implications of screening and treatment strategies. Data from the Framingham Heart Study were used to estimate the time pattern of cholesterol levels, which was fundamental to the evaluation of changing the interval between cholesterol tests. Framingham data were also used to estimate the relation of event rates to blood cholesterol levels. Several components of the analysis were validated by testing model predictions against data from the Multiple Risk Factor Intervention Trial. The cost estimates were based on several additional sources. Individual-level cost-effectiveness estimates for several different interventions were presented along with population-level projections of the consequences of alternative strategies. The significance of altering assumptions about uncertain values, such as the long-term risks and benefits of specific medications, was tested in sensitivity analyses.