Objectives: To evaluate the advantages and effectiveness of the harmonic scalpel (HS) in open thyroid surgery. Background: Haemostasis is the most important factor for successful thyroid surgery. Our aim was to compare the effect of the use of harmonic scalpel versus the conventional haemostasis (CH) methods during open thyroidectomy in the intra-operative and post-operative outcomes. Methods: A retrospective review of all total thyroidectomy operations performed in six years was done. The patients were divided in two groups: The CH group and the HS group according to the method used. Information regarding patient's age, sex, pathological diagnosis, operations details, operations duration, the blood loss, the use of drains and the complications were recorded. Results: Out of 239 operations performed, 143 operations were in the CH group and 96 operations were in the HS group. The average duration of operation was 73minutes in the HS group vs. 97minutes in the CH group, p->0.005. Blood loss was less in the HS group, p- 0.014 with fewer drains, p-< 0.005. Transient hypocalcaemia (TH) was less in the HS group (12.5% vs. 25.9%, p- 0.012). The hospital stay was less in the HS group (3.4 days vs. 3.9 days, p- 0.001). The use of HS was more costly. Conclusion: HS use in thyroid surgery reduces: operation time, blood loss, use of drains, post-operative TH and hospital stay. It is more costly but the advantages of its use in a busy hospital offset this drawback.