Overweight patients with uncomplicated essential hypertension were followed up biweekly for six months: 24 not receiving antihypertensive-drug therapy (Group I) and 83 on regular but inadequate (despite drug manipulation) antihypertensive-drug therapy (Group II). All patients in Group I and 57 randomly selected patients from group II (IIa) participated in a weight-reduction program. The remaining 26 from Group II (IIb) did not receive a dietary program. Salt intake was in the normal range in all three groups. All patients on the dietary program lost at least 3 kg (mean, 10.5 kg), and all but two showed a meaningful reduction in blood pressure; 75 per cent of Group I and 61 per cent of Group IIa returned to normal blood pressure. The weight and blood-pressure reductions were highly significant (P less than 0.001), were present in both sexes and all ages, and were directly associated. In Group IIb, no significant change in blood pressure or weight occurred (P greater than 0.30).