Recent studies have confirmed the benefits of treating hypertension in the elderly. Thiazide diuretics appear to be effective in achieving goal blood pressure in a majority of patients above the age of 60 years. Increasing concern regarding the biochemical abnormalities associated with diuretic therapy has led to the more widespread use of lower doses of these agents. Preliminary results from a study of hydrochlorothiazide +/- amiloride treatment in 99 hypertensive patients aged 65 to 80 years indicate that hydrochlorothiazide 25 to 50 mg/day will lower diastolic blood pressure to less than 90 mmHg in about 90% of elderly patients with mild to moderate elevations in blood pressure. These lower dosages of hydrochlorothiazide were only occasionally associated with mild hypokalaemia. However, the addition of amiloride to the treatment regimen resulted in the maintenance of normal serum potassium concentrations. Thus, relatively low doses of thiazide diuretics may effectively lower blood pressure in elderly hypertensive patients while causing fewer biochemical abnormalities than previously associated with the use of these drugs.