Malfelis badwaterensis, gen.et sp. nov., represented by a nearly complete juvenile skull, isolated I^1–2, P¹, DP², and a fragment of the dentary from the same individual (CM 62590), is described from the early middle Eocene (Gardnerbuttean, early Bridgerian) of the Wind River Formation, Wyoming in North America. M. badwaterensis preserves a unique combination of characters that set it apart from all other creodonts including the presence of a P¹ and reduced M², a carnassial complex from DP^3–4–M¹ with reduced protocones, simplified trenchant P^2–3, and M¹ with conjoined metacone and paracone, and metastylar blade. M. badwaterensis is referred to the Oxyaenidae based on the well-developed metastylar blade of M¹, a reduced M², and loss of M³. This new creodont was perhaps the largest of all animals from the type locality, which has yielded nearly 80 species of mammals.