Purpose: The indication for laparoscopic total or partial adrenalectomy in patients with aldosterone producing adrenal adenoma remains controversial. We compared retroperitoneoscopic partial and total adrenalectomy for aldosterone producing adrenal adenoma in a prospective, randomized, multicenter trial. Materials and Methods: Patients with aldosterone producing adrenal adenoma were randomized to retroperitoneoscopic partial or total adrenalectomy. Patient characteristics, surgical data, complications and postoperative clinical results were analyzed statistically. Results: From July 2000 to March 2004, 212 patients were enrolled in this study, including 108 and 104 who underwent total and partial adrenalectomy, respectively. The 2 groups were comparable in patient age, gender, body mass index and tumor site. Mean follow-up was 96 months in each group. No conversion to open surgery was needed and no major complications developed. Partial adrenalectomy required a shorter operative time than total adrenalectomy but this did not attain statistical significance. Intraoperative blood loss in the partial adrenalectomy group was significant higher than in the total adrenalectomy group (p < 0.05) but no patient needed blood transfusion. All patients in each group showed improvement in hypertension, and in all plasma renin activity and aldosterone returned to normal after surgery. No patient required potassium supplements postoperatively. In the total and partial adrenalectomy groups 32 (29.6%) and 29 patients (27.9%), respectively, were prescribed a decreased dose of or fewer antihypertensive medicines at final follow-up. Conclusions: Retroperitoneoscopic partial adrenalectomy is technically safe. It has therapeutic results similar to those of total adrenalectomy in patients with primary aldosteronism due to aldosteronoma.