To define the time course of regression of left ventricular hypertrophy (LVH) during antihypertensive therapy with beta-blocking agents, 73 hypertensive patients were serially studied by echocardiography during 12-months therapy with beta-blockers. Blood pressure decreased significantly after 1 month and further on after 12 months (from 164 +/- 18/110 +/- 9 to 139 +/- 14/94 +/- 7 mmHg, p < 0.001). Left ventricular (LV) end-diastolic dimension increased significantly after 1 month (from 51.2 +/- 3.9 to 52.2 +/- 4.7 mm, p < 0.01) and decreased after 12 months (50.4 +/- 4.0 mm, p < 0.05). Septal and posterior wall thickness decreased progressively after 1 month and 3 months, respectively. LV mass index decreased significantly after 3 months, and further on after 12 months (from 164 +/- 42 to 145 +/- 33 g/m2, p < 0.001). LV fractional shortening did not significantly change throughout the study. Thus, a reduction of hypertensive LVH occurred after 3 months of therapy with beta-blocking agents and went on during the subsequent months without impairment of LV systolic function.