Abstract Background: Primary hyperhidrosis is a benign and idio-pathic sympathetic disorder characterized by excessive sweet-ing with no apparent underlying cause and is aggravated during periods of stress and anxiety with a prevalence of 0.6- 2.8% of population. Aim of Study: To compare the effectiveness of thoracic endoscopic sympathectomy either at T2 and T3 regarding the patient's satisfaction, compensatory hyperhidrosis and post-operative complications. Patients and Methods: Forty patients between 13 and 30 years old with primary hyperhidrosis undergoing endoscopic thoracic sympathectomy were divided into two equal groups, the group I: T2 (20 patients) endoscopic thoracic sympathec-tomy at T2 ganglion level and group II (20 patients) at T3 ganglion level. Results: All patients in both groups had an immediate improvement after the operation with dry hands and 100% satisfaction. In group I with axillary hyperhidrosis only one patient (33.3%) had axillary dryness While in group II: Three patients (75%) had axillary dryness. In group I: Two patients (40%) had planter dryness while in group II: Three patients (75%) had planter dryness. 12 patients (60%) were complicated by compensatory sweating in group I, and eight patients (40%) in group II (in back, buttock and thigh), the difference was found statistically non-significant. Conclusion: Sympathectomy at the T2 or T3 levels pro-vided adequate long-term treatment for palmar hyperhidrosis in terms of initial surgery results, complications, and patient satisfaction. The most frequent complication was compensatory hyperhidrosis. Because of the lower severity of compensatory hyperhidrosis, we prefer the T3 level for treating palmar hyperhidrosis.