Alteration in the physical properties of arterial blood vessels act as the substrate for end-organ damage and the occurrence of vascular events in hypertension. Structural and functional alteration in the microcirculation represents a prevalent and characteristic abnormality described in the earliest stages of hypertension. In addition to lowering arterial pressure, the importance of reversing structural abnormalities and restoring endothelial function has recently been emphasized. The normalization of microvascular function does not always correlate with blood pressure reduction and might depend on the class of antihypertensive agent employed. Because altered resistance vessel structure and function is a recognized hallmark of hypertension, institution of drug therapy that corrects the associated pathogenic vascular abnormalities is a rational, if unproven, clinical goal.