We examined whether in addition to producing a greater degree of improvement of the arterial stiffness, long-term angiotensin II receptor blocker (ARB) treatment might also have a more beneficial effect on the cardiac diastolic dysfunction than long-term calcium-channel blocker (CCB) treatment; we also evaluated the association between the improvements of the two variables brought about by ARB treatment in subjects with stage I or II hypertension. One hundred and thirteen patients were randomly allocated to treatment with an ARB (candesartan) or a CCB (amlodipine). Echocardiography and measurement of the brachial-ankle pulse wave velocity (PWV) were conducted in both groups at the start of the treatment and at the end of 2-3-years' treatment. After adjustments for covariates, the extent of reduction of the brachial-ankle PWV (-200 ± 18 cm/s vs. -141 ± 18 cm/s, P = 0.03) and that of the increase of the E/A ratio (0.08 ± 0.03 vs. 0.01 ± 0.03, P = 0.04) were significantly greater in the candesartan group than in the amlodipine group. A significant relationship was identified between the delta changes of the brachial-ankle PWV and delta changes of the E/A ratio observed following long-term candesartan treatment. Long-term candesartan treatment may have a more beneficial effect on the stiffness of the large- to- middle-sized arteries than long-term amlodipine treatment, and this treatment may also concomitantly improve the cardiac diastolic dysfunction; a significant association appeared to exist between the improvements of the two variables observed following long-term candesartan treatment.