The effect of bilateral nephrectomy (24 hours before) on the antihypertensive action of dl-propranolol (1 mg/kg iv) was studied in acute neurogenic hypertensive dogs. 2. Bilateral nephrectomy induced an increase in plasma urea and creatinine, a decrease in protein values but did not change the other plasma values (table I). 3. Propranolol always induced a decrease in blood pressure (fig. 1) and heart rate (fig. 2) in bilateral nephrectomized dogs. 4. These results suggest that renal mechanisms (especially modifications of renin release) did not play a predominant or exclusive role in the antihypertensive action of beta-blocking agents under our experimental conditions.