Background: Although a central pressor effect of angiotensinII(ATII) has been implicated in the pathogenesis of hypertension, its effect on hypertensive response to exercise(HRE) is unclear. We hypothesized that HRE would be associated with augmented ATII production during exercise. Methods: Seventy-two consecutive pts who were referred for exercise echocardiography were enrolled. All pts have baseline blood pressure (BP)<140/90mmHg, normal LV function and without any medication. The BP was measured at rest and during supine bicycle exercise(25W, 3 minutes increments). Thirty-six pts (M:F=1:1, age 49짹15) with HRE, defined as difference of peak and baseline SBP���60mmHg in men,���50mmHg in women, and 36 age and gender-matched controls without HRE were compared. The blood was sampled at rest and immediate after peak exercise for measurement of renin, ATII, aldosterone, and catecholamine. Results: There were no significant differences in baseline SBP, DBP, renin, ATII, aldosterone and catecholamine level between two groups. The renin, aldosterone and catecholamine were increased during exercise without significant differences between the groups. However, plasma level of ATII during exercise (p=0.02) and the magnitude of increment of ATII during exercise (1.4짹5.7 vs.16.1짹30.5, p=0.007) were significantly higher in pts with HRE. Conclusion: Despite similar ATII level at rest, HRE was associated with significantly higher ATII during exercise. These findings may provide important information regarding the neurohormonal mechanism in the development of HRE.