PURPOSE: The aim of this study was to compare the surgical completeness and outcome of total thyroidectomy in two patient groups: One treated by harmonic scalpel (HS) and one by conventional total thyroidectomy (CT). METHODS: Between March 2006 and December 2007, 104 patients had total thyroidectomy by HS and 108 patients underwent CT. We analyzed clinicopathological characteristics and stimulated serum thyroid-stimulating hormone (TSH), thyroglobulin (Tg), and anti-Tg antibodies at the time of ablation for both groups. RESULTS: Compared with the CT group, the HS group had shorter operating time and hospital stays and reduced postoperative drainage. At postsurgical ablation, mean serum TSH was 80.47 +/- 21.77 mU/L in the HS group and 69.74 +/- 21.17 mU/L in the CT group, with significant between-group differences (P < 0.001). Mean serum Tg levels after TSH stimulation were 1.57 +/- 3.17 and 3.95 +/- 10.14 ng/mL in the HS and CT groups, respectively, with significant between-group differences (P = 0.028). CONCLUSION: Total thyroidectomy with an HS is a relatively safe and effective technique for use in patients with PTC. The HS provides surgical completeness and has a beneficial effect on successful ablation.