Abnormalities in left ventricular (LV) diastolic function in the presence of normal LV systolic performance is one of the earliest cardiac manifestations of systemic hypertension. Alterations in diastolic filling indices have been observed more clearly in patients with LV hypertrophy, although it is evident that these filling abnormalities may be significantly influenced by age, bodyweight, blood pressure, left atrial size, LV systolic function, interstitial fibrosis, impaired coronary blood flow, and sympathetic stimulation. Several studies indicate that abnormal diastolic function may be responsible, at least in part, for an impaired LV systolic response to isotonic or isometric exercise, even when systolic performance is normal at rest. Short and long term administration of some antihypertensive drugs, such as angiotensin converting enzyme (ACE) inhibitors and calcium antagonists, particularly of the phenylalkylamine type, may significantly improve diastolic function. We observed that abnormal diastolic filling was significantly improved when LV mass was reduced by long term antihypertensive therapy. Even when treatment was withdrawn and blood pressure had increased again, LV mass remained reduced. These results suggest that regression of LV mass might improve LV diastolic function per se. Further studies are needed to assess the effect of improvement of LV diastolic function on the long term prognosis of patients with hypertension.