Total mandibular reconstruction is one of the most challenging modalities in maxillofacial surgery. In this article, we try to introduce a method of total mandible reconstruction. We report a 25-year-old male patient with complete involvement of the mandible by Langerhans cell tumor. The patient underwent total mandibulectomy and reconstruction with bone allograft harvested from a donor who had died the day before. The patient has good functional and aesthetic results in a long time. It seems that bone allograft can be a good alternative to other methods in total mandibular reconstruction.