New associated cranial and postcranial remains of a new genus and species of Mylodontinae: Lestobradys sprechmanni, gen. et. sp. nov (Mammalia: Xenarthra), were found on the coast of Kiyú beach (San José, southern Uruguay). The specimens described are from the late Miocene (Huayquerian SALMA) sediments of Camacho Formation. The mandibular configuration of this new taxon differs from all well-known members of the family in presenting a first alveolus strongly projected toward the labial region that is separated from the rest of the alveoli of the dental series by a marked diastema. It additionally differs in its combination of a subtriangular second alveolus, subquadrangular third alveolus, and a bilobed last alveolus. An incomplete skull, three thoracic vertebrae, and two caudal vertebrae were associated with the mandibular remains. We also refer a complete and well-preserved right astragalus to the new species. Aspects of the history, systematics, and taxonomy of the Mylodontidae and their proposed subfamilies are discussed.