The present study was designed to investigate the potential benefits and limits of two minimally invasive thyroidectomy procedures, namely minimally invasive video-assisted thyroidectomy (MIVAT) and open minimal-incision thyroidectomy (MIT). From May 2000 to June 2006, a prospective, non-randomised study was performed on 957 consecutive patients undergoing thyroid surgery. Fifty-six (5.8%) underwent MIVAT, 214 (22.4%) MIT and 687 (71.8%) conventional thyroidectomy (CT). Patients were selected for MIVAT when total thyroid volume was < or = 30 mL and for MIT when total thyroid volume was > 30 but < or = 80 mL, as determined by ultrasonography. The length of the central neck skin incision was 1.5-2 cm for MIVAT, 2.5-3.5 cm for MIT and 6-10 cm for CT. The incidence of definitive hypoparathyroidism or recurrent laryngeal palsy after MIVAT or MIT was comparable to that occurring after CT. Patients undergoing MIVAT or MIT experienced significantly less postoperative pain than those undergoing CT. Less pain was also registered in the MIVAT patient cohort as compared to the MIT group. Patients undergoing MIVAT or MIT were more satisfied with the cosmetic result as compared to those undergoing CT, whereas no significant differences were found between the MIVAT and MIT groups. As compared to CT, MIVAT and MIT provided a significant improvement in terms of cosmetic results and postoperative pain. Nevertheless, the main limiting factor for minimally invasive thyroid surgery still remains the size of the thyroid.