The aim of this study was to develop a less invasive technique for video-assisted thoracic sympathectomy.A newly designed trocar was used. A skin incision of 2.0 to 2.5 mm in length was made in the third or fourth intercostal space at the midaxillary line. After insertion of the trocar, thoracic sympathectomy with electrocautery was carried out at the level of the second and third ribs.From October 1998 to March 1999, 180 patients with palmar hyperhidrosis underwent this technique. No complications related to the technique occurred, and within 1 week the operative wound had almost completely disappeared. There were recurrences necessitating reapplication of the technique.The technique allowed healing without a scar and improved the patient's cosmesis.