1. Propranolol was given to eight haemodialysed patients with resistant arterial hypertension for periods ranging from 6 to 16 months.
2. The treatment brought about an excellent control of blood pressure in all cases.
3. After withdrawal of propranolol plasma renin activity rose on average 40% compared with the value obtained during treatment. However, no significant relationship was found between the change in plasma renin activity and the change in the diastolic blood pressure.
4. Stopping propranolol resulted in a prompt rebound of arterial pressure toward pretreatment values. However, hypertension was always controlled on resuming drug treatment.
5. The results show that this form of hypertension can be controlled on a long-term basis with propranolol. However, the effect on blood pressure seems not to be mediated by suppression of renin secretion.