Pressure wave reflection plays a pivotal role in the augmentation of systolic blood pressure. In the present study, the association between reflection of pressure wave and structural and functional alteration, including blood flow, in the common carotid artery was investigated in 70 hospitalized essential hypertensive patients. The reflection of pressure was estimated by the "augmentation index" of the carotid arterial pressure waveform. The carotid augmentation index was significantly related to age (r = 0.36), body height (r = -0.30), intima-media thickening (r = 0.28), number of plaques (r = 0.44), stiffness of the carotid artery (r = 0.38), diastolic carotid flow velocity (r = -0.31), and left ventricular mass index (r = 0.33). Furthermore, the reflection of arterial pressure showed a significant negative correlation with diastolic/systolic ratio of blood flow velocity in the carotid artery (r = -0.41, P = .0005). Stepwise regression analysis revealed that age and left ventricular mass index were independent determinants for the carotid augmentation index. These findings indicate that the reflection of arterial pressure is related to morphological and functional alterations of the carotid artery, including a relative reduction of diastolic blood flow.