Thirty patients with uncomplicated essential hypertension were treated for an average of 44 months by 14 internists in private practice. All patients had previously participated in a controlled comparative trial of antihypertensive drugs carried out by the same physicians in their offices. During the long-term follow-up period, ie, after completion of the initial trial, the physicians administered antihypertensive therapy based on their best judgment; the drugs they most commonly prescribed were diuretics (80% of patients) and beta-blocking agents (60% of patients). Although 80% of the patients received at least two different antihypertensive agents, diastolic pressures fell below 96 mmHg in approximately 60% of the patients and below 90 mmHg in only a small fraction. Thus it appears that it is not easy for physicians in private practice to optimally reduce blood pressure levels in hypertensive patients despite the availability of numerous antihypertensive drugs. The tendency of practitioners to approximate blood pressure levels to multiples of 5 or even 10 mmHg may be partially responsible for the unsatisfactory results.