The hemodynamic mechanism of the hypotensive effect of propranolol was studied by quantitative radiocardiography in 8 patients with dialysis-resistant hypertension. Propranolol treatment brought about a decrease in mean arterial pressure and peripheral vascular resistances. The cardiac index was slightly reduced only in the early stage of the treatment. No significant difference was found between patients on treatments lasting longer than 3 months and patients with dialysis-controlled hypertension. The results show that propranolol can be used safely as the sole antihypertensive agent in patients with dialysis-resistant hypertension.