The early detection of hypertension is of foremost concern. It may be that individuals who are normotensive at rest but who show an exaggerated blood pressure (BP) response to exercise are at greater risk of developing hypertension in the future. From exercise tests, a group (ER) of healthy young males who were normotensive at rest (BP less than or equal to 140/90) but showed an exaggerated BP response to exercise (systolic BP greater than or equal to 200 mm Hg and/or diastolic BP 10 mm Hg to greater than 90 mm Hg) were selected. A control group (NR) with exercise BP values less than these were matched for age, weight/height, skinfold thickness, resting BP less than or equal to 140/90, resting heart rate, aerobic fitness level, physical activity, smoking history, and family history of hypertension. After a follow-up period of 5.8 years (range 3 to 14 years) eight of the subjects from the ER group were found to be hypertensive, whereas none of the NR group were hypertensive. Stepwise multivariate regression showed the exercise blood pressure to be the best predictor of future blood pressure of the parameters reviewed in this study. Exaggerated BP response to exercise may serve as an additional risk marker for hypertension.