The aim of this multicentre, double-blind, randomised, controlled study was to evaluate the antihypertensive effect and to determine the response rates, safety and tolerability of 3 doses of carvedilol (25, 50 and 100 mg) compared with those of pindolol 15 mg, in ambulatory patients with mild to moderate uncomplicated essential hypertension. Mean supine diastolic blood pressure was the primary efficacy variable. 205 subjects between 23 and 70 years of age were randomly assigned to receive an oral dose of carvedilol or pindolol once daily for 13 weeks after a placebo run-in period of up to 4 weeks. Before administration of the study medication, blood pressure was recorded at each visit by use of the cuff method, and heart rate was counted. The results showed similar reductions in mean supine diastolic blood pressure among all 4 treatments after 13 weeks. Carvedilol showed a good and similar response rate of approximately 84% at all doses. Heart rate was not significantly changed. The number of patients having adverse experiences possibly related to drug therapy was 4, 16 and 15 with 25, 50 and 100 mg carvediolol, respectively, and 9 with pindolol 15 mg. Dizziness was the most common side effect reported for all medications. In conclusion, carvedilol 25 mg appeared to be the optimum dose in the present study, displaying a high antihypertensive potency with few side effects.