OBJECTIVE To present our experience with retroperitoneoscopic adrenalectomy using 3-mm instruments (mini-rA) for adrenal tumors. METHODS From March 2009 to May 2013, patients with adrenal tumors <6 cm in size and body mass index ≤ 35 were involved in this prospective study and underwent mini-rA performed by 3-mm instruments. Demographic, endocrine and perioperative data, and cosmetic results (using Patient Scar Assessment Questionnaire and Scoring System) were recorded and analyzed. RESULTS Fifty procedures were performed in 48 patients. All procedures were performed with neither conversion to open surgery nor reoperation or mortality. Median operative time and blood loss were 90 minutes (range, 45-210 minutes) and 50 mL (range, 20-210 mL), respectively. Only 1 intraoperative complication (2%) was recorded. Conversion to conventional laparoscopy was needed in 4 procedures (8%). Postoperative complications were recorded in 6 cases (Clavien grade ≤ 2). No differences were recorded in terms of perioperative variables when comparing procedures performed in patients having secreting tumors (n = 18) with other ones (n = 32). On the contrary, procedures performed in patients having benign lesions (n = 41) had significantly lower operative times and complications with respect to those performed in patients with malignant lesions (n = 9). Median Patient Scar Assessment Questionnaire score was 30 (minimum score 28 = the best result; maximum score = 112, the worst result). CONCLUSIONS In selected population, mini-rA is a feasible, safe, and effective technique in the treatment of adrenal masses <6 cm in size, offering objectively proven excellent patients' satisfaction with symptoms and cosmesis. Significant experience before embarking in this kind of surgery is recommended.