Background: There are different techniques for thoracoscopic sympathectomy for management of primary hyperhidrosis. Each technique has the advantage of giving good surgical results but may cause complications which depend on the level of sympathectomy used in each technique. Method: From October 2012 to August 2016, a total number of 120 patients (of primary palmar and axillary hyperhidrosis) were enrolled in this prospective randomized study. Patients were randomized preoperatively and divided into two groups: group A (underwent T2, T3, and T4 sympathectomy), and group B (underwent T3 and T4 sympathectomy) with one year of follow-up. Improvement of palm sweating, development of complications, patient satisfaction and quality of life were evaluated. Results: Family history was positive in 33 patients (55%) in group A and in 31 patients (52%) in group B. All patients had improvement of hand sweating. Over dry hands were significant in group A (p value = 0.032). Compensatory sweating was significant in group A after the first month (p value = 0.016), after 6 months (p value = 0.022) and after 12 months (p value = 0.025). In group B, very satisfied patients were significant after 6 and 12 months (p value = 0.002 and 0.000 respectively). Conclusion: Limited sympathectomy to the level of T3 and T4 has the same therapeutic effect obtained by T2, T3 and T4 sympathectomy with less complications, more patients' satisfaction and better quality of life. It should be the technique of choice for treatment of primary palmar and axillary hyperhidrosis.