Objectives: to identify the benefits of harmonic scalpel in thyroidectomy relating to the length of incision, operation time, postoperative pain, and complications. Method: A prospective study of 196 thyroidectomy patients was performed in Head and Neck Surgery Department, HCMC Oncology Hospital from 30/03/2010 to 15/08/2010.Results: The length of incision was 5.5 cm.