목적: The choice of optimal method among various gland preserving procedures depends on the size of submandibular gland stone. We tried to assess the accuracy of ultrasound and computerized tomography (CT) for determining submandibular gland stone size 방법:We retrospectively analyzed ultrasound and non-contrast neck CT images of 80 patients with submandibular gland stones who underwent each study and transoral surgery from January 2008 to December 2014. The patients who have multiple stones, who have incomplete medical record, or whose stones were split during surgery were excluded. Records of ultrasound and CT measurement of maximal stone diameter were compared to records of postoperative measurement of removed stones. 결과:The submandibular gland stone size was measured as mean 6.6 mm (SD 3.8) by Ultrasound, mean 7.23 mm (SD 4.0) by neck CT, and mean 7.89 mm (SD 4.7) by postoperative measurement. Correlation coefficient was 0.921 between USG and postoperative measurement and 0.94 between CT and postoperative measurement. (P = 0.000 and 0.000, respectively). The location of stone and presence of combined infection showed no significant impact on the accuracy of ultrasound and CT measurement. 결론:Ultrasound and neck CT showed high accuracy for prediction of submandibular gland stone size. However, neck CT could be considered as a better tool for estimating submandibular gland size than ultrasound.