A rare pathological mandible, manifesting bilateral absence of the condyles, is discussed. The pathology was identified as hemifacial microsomia. The mandible, dated to the Byzantine period in Israel, manifests bilateral aplasia of the condyles and extreme shortness, but normal width, of the body. The extremely well-developed coronoid process, the grooved masseter insertion area, and the manifestation of a medial pterygoid tubercle (MPT) suggest hypertrophy of the occlusal muscles. The presence of a large MPT is considered a Neandertal autapomorphy. Studying the biomechanic forces acting on the deformed mandible in hemifacial microsomia patients may shed light on the mastication process in Neandertals. Am J Phys Anthropol 111:135–139, 2000. © 2000 Wiley-Liss, Inc.