Beginning in April 1989, we have performed eight upper thoracic chemical sympathectomies by transthoracic endoscopy. The indications were occlusive arterial disease in four patients and Raynaud's syndrome and palmar hyperhidrosis in two patients each. Transthoracic endoscopy was performed under general anesthesia, through the third costal interspace on the anterior mid-clavicular line. Five ml of phenol were injected into the parietal pleura covering the three proximal thoracic ganglia. The duration of thoracic drainage was 24 hours. The postoperative course was uneventful except for one case of subcutaneous emphysema and transient Horner's syndrome in three instances. There were no initial failures. Because of its simplicity and the short hospitalization period, chemical sympathectomy by transthoracic endoscopy constitutes a valuable alternative to conventional surgery. This technique is, however, limited in the case of antecedent pleuropulmonary disorders.