A recently added goal in the control of primary hypertension is the reversal of left ventricular hypertrophy which may occur early in the disease and which can have serious consequences. We have attempted to define the hemodynamic parameters which distinguish most sensitively between the long-term effects of two antihypertensive drugs, alpha-methyldopa and propranolol, with a view to determining the optimal conditions under which each of the drugs may be used therapeutically. Twenty matched hypertensive patients, all with established left ventricular hypertrophy, were divided at random into two groups who received either alpha-methyldopa or propranolol as monotherapy. Dosage was titrated until blood pressures were normalized (diastolic blood pressure (DBP) ≤ 95 mmHg) (1 mmHg = 133.322 Pa); then therapy was maintained for 48–52 weeks. Supine and erect blood pressures, heart rates, and eight echocardiographic indices were recorded before commencement of therapy and at the 48- to 52-week period. Stepwise discriminant analysis identified erect DBP, erect heart rate, and posterior wall thickness of the left ventricle as being the parameters which distinguished most clearly the therapeutic effects of the chosen drugs. Using these three parameters, all 20 patients were correctly classified into their respective drug groups. We propose that these results may form the basis of a more rational choice of antihypertensive therapy with alpha-methyldopa or propranolol for hypertensive patients based on the initial determination of these three parameters.