To study whether restoration of a normal circulatory system could be achieved with antihypertensive treatment, 13 hypertensive men with structural cardiovascular changes and 37 normotensive control subjects were investigated by echocardiography, apexcardiography, plethysmography, inulin and p-amino-hippurate clearance, and determination of 24-hour urinary excretion of albumin, first at age 49 years and again seven years later. All men were untreated at the first investigation. Immediately thereafter, therapy with the cardioselective beta-adrenoceptor blocker metoprolol tartrate was initiated in the hypertensive men. Seven years of antihypertensive treatment resulted in (1) normalization of central and peripheral hemodynamic variables, (2) reversal of left ventricular hypertrophy in proportion to achieved blood pressure control, (3) normalization of systolic wall stress and a well-preserved systolic left ventricular function, (4) normalization of diastolic left ventricular function, and (5) normalization of increased microalbuminuria and a decrease in renal vascular resistance, with no change in glomerular filtration rate compared with control subjects. In conclusion, the findings strongly indicate that regression of cardiovascular structural changes can be achieved with long-term antihypertensive treatment.