To assess the long-term predictive importance of high cardiovascular reactivity in relation to subsequent blood pressure, 51 men from a pool of 204 men originally tested at age 18 to 22 years were recruited for blood pressure assessment 10 to 15 years later. Initial testing uniformly involved monitoring of systolic pressure, diastolic pressure, and heart rate during a reaction time task involving threat of shock. In 30 of the 51 men who participated at follow-up, initial testing had also included separate visits to obtain relaxation-only baseline levels of the cardiovascular indices. At follow-up, in addition to clinic-type stethoscopic determinations, blood pressure and heart rate were assessed during work and social and leisure activities via ambulatory monitoring. Men with higher levels of systolic pressure during the task showed higher stethoscopic and ambulatory systolic pressure at follow-up. Likewise, men with higher levels of diastolic pressure during the task showed higher diastolic levels at follow-up. In the 30 men with both good task and baseline data from initial testing, those with high heart rate reactivity (task minus baseline) showed higher systolic, diastolic, and heart rate levels at follow-up than low heart rate reactors, even though their baseline blood pressures had not differed at initial testing. Similarly, men with high systolic reactivity showed higher diastolic pressure at follow-up than low systolic reactors. Multiple regression analyses also demonstrated that systolic, diastolic, and heart rate reactivity improve prediction of follow-up blood pressure when added to models incorporating the standard risk factors, baseline blood pressure, and parental history of hypertension.