During the last 15 years 8 patients were diagnosed with renin secreting juxtaglomerular cell tumors among 30,000 hypertensive patients. Clinical characteristics included severe hypertension poorly medically controlled in young patients (mean age 22.3 years) and severe hypokalemia (mean 2.83 mmol./l.). Secondary hyperaldosteronism was present in all cases with a constant elevation of renin activity. Renal vein sampling was only positive in 64% of cases. Selective renal arteriography demonstrated an avascular area in 43% of the patients. Computerized tomography showed the tumor in all cases. Mean tumor size was 24 mm. (range 10 to 50). Conservative surgery was feasible in all patients. Perioperative ultrasonography was used for 3 intraparenchymal tumors. Hypertension and hypokalemia resolved within 1 week after surgery. At a mean followup of 98 months (range 24 to 204) no tumor recurrence was documented.