Using digitized M-mode echocardiograms and 24-hour noninvasive ambulatory blood pressure monitoring, we evaluated the effects of 1 year treatment with amlodipine on left ventricular morphology and function in 10 hypertensives with left ventricular hypertrophy. Echocardiograms and 24-hour blood pressure monitoring were performed after 3 weeks of wash-out and after 1 year of oral treatment with amlodipine (5 mg once daily). The therapy significantly lowered blood pressure, without changes in heart rate. Left ventricular mass decreased in all the patients and peak lengthening rate of left ventricular diameter, index of diastolic function, increased in all, with normalization in 5 of the 6 with basal diastolic impairment. Peak shortening rate of left ventricular diameter, index of systolic function, was normal in all at the basal evaluation and did not change after therapy. The percentage reduction of left ventricular mass index significantly correlated with percentage decrease of 24-hour and day-time systolic and diastolic blood pressure. Amlodipine is able to induce regression of left ventricular diastolic function and no changes of systolic function.