Hypertension and aging are both associated with changes of left ventricular (LV) diastolic filling and increased LV mass. To determine whether diastolic filling abnormalities are present in hypertension independent of aging and significant hypertrophy, we studied 19 hypertensive patients following a period of 4 weeks when they were not receiving therapy and 18 normotensive subjects matched for sex, age, and LV mass. All subjects had normal systolic function and ejection fraction as assessed by radionuclide angiography. We measured peak velocity of early filling (E), late filling (A), and their ratio (E/A) by Doppler echocardiography. Filling indices were abnormal in hypertensive patients, but none of the filling indices were significantly correlated with LV mass. E was inversely related to age (r = -0.62; p less than 0.01) and diastolic blood pressure (r = 0.45; p less than 0.05) in normotensive individuals, but these correlations were not significant in hypertensive patients. E was not significantly correlated to LV mass or wall thickness. In contrast, A was influenced by septal wall thickness and blood pressure in both groups. E/A correlated inversely with age in both normal individuals (r = -0.74) and hypertensive patients (r = -0.51). These findings indicate that diastolic filling abnormalities in hypertension are not solely caused by either LV hypertrophy or by aging and therefore must be in part related to the hemodynamic load or altered myocardial or chamber properties.