Hyperhidrosis, one of the abnormalities in autonomic nervous system, has been treated with dermatologic principles or thoracic sympathectomy via conventional axillary thoracotomy or dorsal spinal approach. But these techniques were rather ineffective or invasive. Recently, VATS is widely applied in thoracic surgical area, and hyperhidrosis is not the exception of these cases.From May 1993 to August 1994, 30 patients with bilateral palmar hyperhidrosis underwent bilateral thoracic [T2, T3 sympathectomy with thoracoscopic surgery at Seoul National University Hospital. There were 20 men and 10 women and the mean age was 23.0 years.Mean operating time was 115 min and there was no thoracotomy conversion. Operative complications were anesthetic overdose in 1, Horner`s syndrome in 1, and small amount of residual pneumothorax in 6. Mean postoperative hospital stay was 2.3 days [range from 1 to 4 days and postoperative analgesics were required in 17 cases with a single dose.Sweating amount was measured in 12 patients, showing significantly decreased amount from 284.5 mg preoperatively to 18.9 mg postoperatively in 5 minutes [p=0.004 . There was no recurrence during mean 6 months follow up. Twenty two patients [73.3 % complained moderate compensatory hyperhidrosis on the trunk.In conclusion, all patients were greatly satisfied with those results including no more palmar sweating, less pain, better cosmetics, short hospital stay. In addition, recent use of sweating amount measurement and intraoperative temperature monitoring could make this technique more accurate, so we easily applied thoracoscopic sympathectomy with minimal risk.