Excessive sweating of the palms, axillae, and face has a strong negative impact on the quality of life for many people. The existing non-operative therapeutic options seldom give sufficient relief and have a transient effect. But a definitive cure can be obtained by upper thoracic sympathectomy. From June 1997 to October 1997, 117 cases of the needle (2 mm) thoracoscopic thoracic sympathectomies were performed in the Department of Thoracic and Cardiovascular Surgery in the Respiratory Center Yong-dong Severance Hospital in Seoul, Korea. We have followed up on 94 cases which include palmar hyperhidrosis (n=85), facial hyperhidrosis(n=5) and axillary hyperhidrosis(n=4). There were 42 males and 52 females whose ages ranged from 14 to 63 years(median:23 years). The T2 ganglia and T3-4 ganglia were excised by electrocuting with a hook and endoscissors and were removed for histologic examination. There have been no mortalities or life-threatening complications. The surgical results were classified as excellent(much improvement,very dry) in 93.6%, good(some improvement, minimally wet) in 2.1%, and fair(slight improvement, still wet) in 4.2%. Five patients(5.3%) required closed thoracostomy drainage because of pneumothorax in the immediate postoperative day. Horner's syndrome occurred in one case. The compensatory sweating occurred in 67 cases(71.2%) and was embarrassing in 21 cases(22.3%) and disabling in 9 cases(9.6%) of these cases. Primary failure occurred in one case. The patient with primary failure underwent successful operation. Fifty-one patients had concomitant hyperhidrosis. Our experiences indicate needle thoracoscopic sympathectomy is a very effective, safe, and time- saving procedure for essential hyperhidrosis.