Among the 356,222 men screened for the Multiple Risk Factor Intervention Trial who had no history of hospitalization for heart attack at entry, more than 2,000 coronary deaths occurred during 6 years of follow-up. With this large data set, detailed cross-tabulations clearly and simply showed the strong graded relation between blood pressure and coronary heart disease death. This risk gradient was evident in each of five age groups ranging from 35 to 57 years and for levels of diastolic blood pressure ranging from less than 75 mm Hg to greater than 115 mm Hg. Systolic blood pressure was more strongly associated with coronary heart disease death than was diastolic blood pressure, and isolated systolic blood pressure elevation was found to be an important risk factor in these middle-aged men. The risk of coronary death was increased among hypertensive men who had elevated serum cholesterol levels or who smoked cigarettes. Because less than 10% of hypertensive men had cholesterol levels in the lowest quintile (below 182 mg/dl) and were nonsmokers, a multi-intervention approach for the large majority of hypertensive persons is clearly indicated. Risks of death were also substantially increased among those hypertensive men who already had end-organ damage, emphasizing the importance of early treatment to prevent such damage. These findings have implications for the design of prevention trials and clinical practice, as it is clear that systolic as well as diastolic blood pressure should be considered in treating hypertensive patients. Additionally, treatment goals should be directed at preventing not only death but many other morbid events, clinical and subclinical, that are associated with elevated blood pressure and that are preventable with appropriate treatment.