Endoscopic thoracic sympathicotomy, or sympathectomy by a 2-mm scope, is an effective method for treating palmar hyperhidrosis. However, postoperative compensatory sweating may be troublesome in some patients. We report needlescopic T2 sympathetic block by clipping, which may provide reverse operation for patients encountering compensatory sweating. Between January 1998 and January 2002, a total of 102 patients with palmar hyperhidrosis underwent video-assisted thoracoscopic sympathetic blocking of the T2 ganglion. There were 47 males and 55 females (mean age, 24.1 years; range, 9-50 years). All patients were placed in a semi-sitting position under single-lumen intubated anesthesia. We performed T2 sympathetic block by clipping at the second and third intercostal spaces using a 2-mm, 0 degrees thoracoscope. Among these 102 patients, all bilateral T2 sympathetic blockings were achieved. The operation was usually accomplished within 30 minutes (range, 16-40 minutes). All patients were discharged within 4 hours after the operation. There were no surgical complications or surgical mortality cases. The mean postoperative follow-up period was 37.1 months (range, 16-64 months). Improvement of palmar hyperhidrosis can be obtained in all patients. Eighty-six patients (84%) have developed compensatory sweating of the trunk and lower limbs. Two patients had a reverse operation and had improvement of compensatory sweating at 2 and 13 days after removal of endo clips. Needlescopic T2 sympathetic block by clipping is a safe and effective method for treating palmar hyperhidrosis; compensatory sweating may be improved after reverse operation removal of endo clip.