The potential benefits of a high-risk and a population strategy to prevent cardiovascular disease deaths by lowering total serum cholesterol and diastolic blood pressure were estimated. The first strategy concentrates on the top 10% of the risk distribution, and the second strategy changes risk factor distributions of the entire population. With the high-risk strategy, lowering total serum cholesterol 20% and diastolic blood pressure to 90 mmHg would result in a 28% reduction in death from cardiovascular disease. Lowering total serum cholesterol to 190 mg/dl and diastolic blood pressure to 80 mmHg with this strategy would result in a 33 per cent reduction in death from cardiovascular disease. These expected changes approximate those expected by lowering total serum cholesterol by 10% and diastolic blood pressure by 5% with the population strategy. Changes in total serum cholesterol (20% lowering) and diastolic blood pressure (10% lowering) that have been achieved in nutrition intervention trials would result in a 50% decline in cardiovascular disease death rates if applied to the whole population. If population mean total serum cholesterol could be lowered to 190 mg/dl and population mean diastolic blood pressure could be lowered to 80 mmHg, a 70% reduction in cardiovascular disease death rates would be expected. This suggests that only a population approach can prevent the majority of deaths from cardiovascular disease in a community.