Voice alteration is an important complication of thyroid surgery and is closely related to patients' quality of life. There are no studies analyzing effect of energy-based devices (EBD) on voice quality (VQ). Aim of this prospective study is to evaluate impact of sutureless total thyroidectomy performed with EBDs on objective voice parameters of patients without recurrent laryngeal nerve (RLN) and/or external branch of superior laryngeal nerve (EBSLN) injury. Sixty patients underwent total thyroidectomy with meticulous dissection of EBSLN. Patients were assigned to Group L (Ligasure (TM)), Group H (Harmonic), or Group C (Conventional) through random ballot. For analysis of alteration in VQ, digital videolaryngostroboscopy (VLS), voice handicap index (VHI), multidimensional voice program (MDVP), and electroglottography (EGG) were used. VLS was performed by 70A degrees-angled indirect laryngoscopy and evaluation was standardized by VLS scale and laryngeal function scoring. This study is registered on clinicaltrials.gov with number NCT01865006. Forty eight patients were female. There was no difference on demographic data. On post-operative laryngoscopic examination, none of the patients had vocal fold palsy. When mean VHI scores at post-operative 1st week and 2nd month were compared to pre-operative values for each groups, groups L and H demonstrated a significant increase in VHI in the early post-operative evaluation, while there was no significant increase for group C. No significant increase was seen in late post-operative period compareYd to pre-operative period for any groups. In the early post-operative period, VQ is better with the conventional technique than EBDs; however, in late post-operative period, VQ is detected better in EBDs (especially in Group L) than the conventional technique, but no statistical difference was observed.