The determination of the volume of a diseased thyroid lobe or an entire gland by preoperative ultrasonography may enable surgeons to select candidates for a minimally invasive approach to thyroid lobectomy or total thyroidectomy. We retrospectively reviewed the charts of 71 adults who had undergone minimally invasive nonendoscopic thyroid surgery at our hospital from January 2007 through May 2009. We compiled data on ultrasonic preoperative thyroid volumes and operative incision lengths. Of the 71 patients, 40 had undergone lobectomy and 31 had undergone total thyroidectomy. The lobectomy group was evenly subdivided into two groups based on the median volume of the affected lobe; 20 patients had a volume of <28.32 ml and 20 had a volume of >28.32 ml. The incision length ranged from 2.0 to 3.8 cm (mean: 3.1 ± 0.53) in the smaller-volume lobectomy group and from 2.5 to 5.0 cm (mean: 3.7 cm ± 0.71) in the larger-volume lobectomy group; the difference was statistically significant (p < 0.01). The 31 patients in the total thyroidectomy group were subdivided on the basis of the median volume of the entire thyroid gland; 16 patients had a volume of <49.24 ml and 15 had a total volume of >49.24 ml. The incision length in those two groups ranged from 2.5 to 4.0 cm (mean: 3.4 ± 0.53) and 3.6 to 6.0 (mean: 5.1 ± 0.99), respectively; again, the difference was statistically significant (p < 0.001). The findings of our study suggest that preoperative ultrasonographic thyroid lobe volume or total thyroid gland volume can be used to determine the appropriate minimum length for the surgical incision.