Clinical drug trials have shown that pindolol, timolol and sotalol are effective hypotensive agents in Nigerians with mild to moderate hypertension (standing diastolic blood pressure below 120 mmHg). There was no significant difference between the three beta-blockers with respect to their antihypertensive effect irrespective of differences in their other pharmacological actions. There was also no correlation between the hypotensive effect of the drugs and the initial blood pressure. Timolol at 30 mg daily had an additive effect to the hypotensive action of binazine, a peripheral vasodilator. Increasing the dose of timolol to 60 mg daily did not produce further fall in the blood pressure. Pindolol at a dose of 30 mg per day also had an additive effect to the hypotensive action of the thiazide diuretics, methyldopa and debrisoquine. There was no significant difference between the hypotensive effect of sotalol and that of methyldopa. The three beta-blockers produced no side effects. This was considered to be a distinct advantage over most of the drugs currently available for treatment of hypertension in Nigeria.