The two cases presented here involved complex composite odontomas that had become cystic. They were very different in appearance; the first case being almost classic and the second case showing more bizarre configuration and being associated with a much larger cystic cavity. Two different surgical approaches were used. In the first case a bone graft from the iliac crest was used to fill the extensive mandibular defect. In the second case, enucleation with good primary closure was thought to be sufficient since good bony margins were evident and the likelihood of pathologic fracture was considered minimal.