Odontogenic myxoma is a rare intraosseous neoplasm, which is benign but locally aggressive. It rarely appears in any bone other than the jaws. It is considered to be derived from the mesenchymal portion of the tooth germ. Clinically, it is a slow-growing, expansile, painless, non-metastasizing, central tumor of jaws, chiefly the mandible. Here we report the case of a typical odontogenic myxoma in a 26-year-old female patient, which had acquired large dimensions and involved the entire left half of the mandible including the ramus, resulting in a gross facial deformity, within a span of one and a half years.