Breast lymphedema (BLE) has been reported as a complication following breast cancer treatment. As for extremity lymphedema treatment, supermicrosurgical lymphaticovenous anastomosis (LVA) is considered an option for the treatment of progressive BLE refractory to conservative treatments, but no case has been reported so far. We report the first case of BLE successfully treated with supermicrosurgical LVA. A 55-year-old female presented with left BLE after breast conserving surgery and axillary lymph node dissection and adjuvant radiotherapy. After the cancer treatments, the patient suffered from pronounced swelling, sensation of tension, and pain of the left breast with frequent episodes of breast cellulitis. Conservative treatments had been performed for 7 years, but were not effective, and the patient was referred for further surgical treatment. Supermicrosurgical LVA was performed at the left breast. LVA surgery resulted in three anastomoses, in which three lymphatic vessels were anastomosed to three nearby veins in an intima-to-intima coaptation manner. After LVA, the left breast decreased in size, and the sensation of tension disappeared. One year postoperatively, the patient had no distress nor cellulitis episode, and was satisfied with the results of normal breast conditions. Although further clinical studies are required to confirm efficacy, supermicrosurgical LVA has the potential to be an option for the treatment of progressive BLE refractory to conservative treatments.