Patagosmilus ("Patagonian knife" in Greek) is an extinct genus of meat-eating metatherian mammal of the Thylacosmilidae family, that lived in the middle of the Miocene in South America. Like another representatives of this family, like Thylacosmilus atrox and Anachlysictis gracilis, it was characterized by its elongated fangs of the upper jaw, similar to the well known "sabertooth cats" (Machairodontinae), which they were ecological equivalents. The general morphology of Patagosmilus suggest that it was less specialized that the latest Thylacosmilus of the Pliocene, but the shape of the teeth, indicates that probably was more related to the former than the even more primitive Anachlysictis of Colombia.