Mandible is the biggest and the hardest facial bone and its shape is found well-remained in the fossil and forensic research area. Therefore it is of significance in physical anthropology and it has been used to distinguish the different ethnic groups as well as the sex. The researchers took 102 mandibles in Korean of the known sex and examined the physical anthropologic characteristics that exist among the Korean males and females as well as the different ethnic groups. Through examining 13 criteria that include the shape of the chin and the shape of mental spine the following results were achieved. Out of the 13 non-metric criteria of the examined mandibles, Concerning the sexual dimorphism, the most distinguished criteria was the contour of the mandibular lower border. In males, 68.1% showed the "rocker form", on the other hand in females, the "straight form" was more general (82.0%). In addition, the shape also differed in mental region. In males the shape of the chin was bilobate or square form generally (91.7%), while females' mandible wasn't bilobate form, but square (53.6%) and pointed form (46.4%). Beside this, there was no differences between the male and female. We compared in presence of mylohyoid canal in Korean with the other ethnic groups by non-metric traits. The mylohyoid canal was relatively low by 5% among the Asians including the Koreans and relatively high by 10.0% among the Whites and over 15.0% among the Blacks.