Thoracoscopic sympathectomy has emerged in recent years as the treatment of choice for primary palmar hyperhidrosis when medical treatment fails. Postoperative complications have been reported in large series, however, including neurologic problems such as temporary or definitive Horner syndrome and peripheral nerve injuries. The authors report the use of ultrasonic coagulating scissors instead of electrocautery for the dissection and removal of a segment of sympathetic chain in an 11-year-old girl. A bilateral procedure was performed sequentially through three 5-mm axillary trocars on each side. The use of ultrasonic shears eliminates the risk of distal nerve injury induced by the spread of electric current and could possibly reduce the incidence of the above-mentioned complications.