The authors investigated the accuracy and reliability of three-dimensional and reformatted computed tomographic images by comparing direct measurements on the dry mandible and the measurements on three-dimensional and reformatted computed tomographic images of the dry mandible. 29 Korean dry mandibles were imaged and 16 items of measurements were measured. The results were as follows; 1. The correlation coefficients between the two methods were between 0.95 and 0.99, except for the measurement of Go-Pg. 2. The mean differences of the measurements between the two methods ranged from -0.52 to 0.42mm and the range of standard deviations for these mean differences was. 0.28 to 2.70 mm. 3. Of the difference scores in total measurements, 75.9% were within 1mm and 95.9% were within 2mm. In conclusion, the agreement between the two methods was excellent and the measurements of the three dimensional and reformatted computed tomographic images were reliable. The three-dimensional and reformatted computed tomographic images can be an useful method in anthropologic study.