Mylohyoid bridging on the mandible is a hyperostotic variation considered as one of the cranial non-metric characteristics. Most researchers have indicated that such non-quantitative traits can be used for the investigation of population history and these traits show differences according to societies. In the present study, we investigated the incidence of mylohyoid groove bridging on 89 half-mandibles (48 right sides, 41 left sides; 39 complete mandibles, nine right and two left half-mandibles) from the Byzantine period, dated approximately eight centuries back. We observed that the incidence of mylohyoid bridging was 8.9% for the Byzantine mandibles with no side predilection. The incidence of bridging observed in the present sample was compared with those of earlier studies. Mylohyoid bridging may be useful as a non-metric feature in population studies when used in combination with other characteristics. © 2006 Japanese Association of Anatomists.