Aortic stenosis (AS) is a common valve disease, affecting nearly 5% of elderly individuals. Because most common etiology of AS is degenerative valve disease, hypertension (HT) is not rare in patients with AS. It was reported that more than 30% of patients with AS had systemic hypertension. Therefore, management of hypertension is an important issue for these patients. There are several effects of combined AS and HT. First, HT increases hemodynamic load of left ventricle and peak systolic left ventricular wall stress. Valvulo-arterial impedance (Zva) has been suggested as a marker of global left ventricular hemodynamic load that represents the cost in mmHg for each ml of blood pumped by left ventricle during systole. Zva is calculated as follows; (systolic blood pressure+mean transportic pressure gradinet)/stroke index. It has been reported that Zva is an important prognostic marker in AS patients. Paradoxical low-flow low-gradient AS is a typical example. Despite relative low pressure gradient less than 40mmHg, those patients shows high Zva and worse prognosis, and may need valvular replacement. Second, HT affects transaortic pressure gradient. In animal experiment, increase of systemic blood pressure itself lowers transaortic pressure gradient in AS. Therefore, measurement of blood pressure is essential in the assessment of AS. Traditionally, active blood pressure loweing was not recommended becasue of the risk of syncope. Currently, no published guidelines provide strong recommendation for the management of HT in AS patients. However, several recent studies demonstrated that the risk of stroke is low and similar to that seen in AS patients without HT. In conclusion, HT is not uncommon in AS patients. Because it increases hemodynamic load of left ventricle and may affect badly in long-term prognosis, careful but active lowering of blood pressure may be warranted for those patients.