INTRODUCTION: Level T4 video-assisted thoracoscopic sympathectomy proved superior to T3-T4 treatment for controlling axillary hyperhidrosis at the initial and six-month follow-ups of these patients. OBJECTIVE: To compare the results of two levels of sympathectomy (T3-T4 vs. T4) for treating axillary sudoresis over one year of follow-up. METHODS: Sixty-four patients with axillary hyperhidrosis were randomized to denervation of T3-T4 or T4 alone and followed prospectively. All patients were examined preoperatively and were followed postoperatively for one year. Axillary hyperhidrosis treatment was evaluated, along with the presence, location, and severity of compensatory hyperhidrosis and self-reported quality of life. RESULTS: According to patient reports after one year, all cases of axillary hyperhidrosis were successfully treated by surgery. There were no instances of treatment failure. After six months, compensatory hyperhidrosis was present in 27 patients of the T3-T4 group (87.1%) and in 16 patients of the T4 group (48.5%). After one year, all T3-T4 patients experienced some degree of compensatory hyperhidrosis, compared to only 14 patients in the T4 group (42.4%). In addition, compensatory hyperhidrosis was less severe in the T4 patients (p < 0.01). Quality of life was poor before surgery, and it improved in both groups at six months and one year of follow-up (p = 0.002). There were no cases of mortality, no significant postoperative complications, and no need for conversion to thoracotomy in either group. CONCLUSION: Both techniques were effective for treating axillary hyperhidrosis, but the T4 group showed milder compensatory hyperhidrosis and greater patient satisfaction at the one-year follow-up.