Clinical practice often conflicts with epidemiologic evidence in the management of blood pressure. Antihypertensive therapy is generally prescribed if blood pressure exceeds some arbitrary level, thus committing many persons with minimal cardiovascular risk to long-term drug therapy. By contrast, below that level, regardless of cardiovascular risk, blood pressure reduction is rarely sought. Epidemiologic data, however, consistently show a continuous, positive, linear relationship of the height of both systolic and diastolic blood pressure with the incidence of stroke and heart attack. No threshold level distinguishes those who will have a cardiovascular event from those who will not. In fact, most heart attacks and many strokes occur among persons with "normal" blood pressures. Observational experience suggests that benefit could be obtained from universal blood pressure reduction of even a few millimeters of mercury. This public health strategy can be augmented by identifying those individuals, at every level of blood pressure, whose risk for cardiovascular disease justifies the cost of pharmacologic intervention. Antihypertensive drug therapy will be most efficient and effective if directed at those who, by virtue of their constellation of risk factors or evidence of preclinical vascular disease, are likely to have a heart attack or stroke. The resulting redirection of clinical resources will spare many hypertensive persons whose absolute risk for a cardiovascular event is small, from life-long treatment. At the same time, other persons, currently classified as normotensive, will become candidates for blood pressure reduction because their cardiovascular risk is high.