BACKGROUND: Thoracoscopic R3 (above the third rib)sympathicotomy has been performed as an effective method in treating palmar hyperhidrosis because it is effective in eliminating the symptoms of hyperhidrosis and has lower degree of compensatory hyperhidrosis than that of sympathectomy. Most of the results published were based on the short-term follow up. So we evaluated the intermediate term follow up results of the R3 sympathicotomy. MATERIAL AND METHOD: From April 1999 to August 2001, ninety-four patients with palmar hyperhidrosis had been treated by R3 sympathicotomy at the Inha University Hospital. Follow-up study was completed for 76 patients (male 38, female 38) and average follow-up period were 25+/-9.1 (15~50) months. The sympathetic trunk passing above the upper border of third rib was divided by electric cautery. The patient's satisfaction after surgery was estimated using the analogue scale from score 0 to 100 (100 means perfect satisfaction). RESULT: The scale of patient's satisfaction immediately after operation was 92.36+/-9.93. After 15 months, the scale of satisfaction was decreased to average 71.80+/-20.24 and it is statiscally significant. The cause of dissatisfaction were compensatory hyperhidrosis and recurrence of symptom. The degree of sweating immediately after operation was mean 0 and after 15 months it increased to mean 1.5. The degree of the compensatory hyperhidrosis immediately after operation was mean 1 and it increased to mean 5 after 15 months. CONCLUSION: R3 sympathicotomy has excellent therapeutic results immediately after operation but therapeutic effectiveness is becoming to decrease 15 months after operation. The common causes of dissatisfaction are compensatory hyperhidrosis and recurrence of hyperhidrosis.