Metastatic tumors to the oral cavity are rare and account for approximately 1% of all malignant oral neoplasms. About 765 cases have been published in the English- and Chinese-language literature since 1950, with less than 6% of these cases corresponding to prostate cancer metastasis. Because of their uncommon incidence, the diagnosis of oral metastases, especially those originating from the prostate gland, may represent a challenge for general dentists, oral pathologists, and oral radiologists. Thus, the aim of this study was to describe an interesting case of prostate adenocarcinoma metastasizing to the posterior mandible. In addition, association with numb chin syndrome present in this case was discussed.