Altacreodus

 ( Pan-carnivora ) 

Altacreodus ("Creodonta from Alberta") is an extinct genus of . Fossils have been found in North America where they first appeared during the Late Cretaceous, and they died out prior to the start of the Paleocene. It is possibly one of the earliest known placental mammals in the fossil record.

The type species is " Cimolestes" magnus, which was renamed Altacreodus magnus in 2015. Based on the dimensions of its preserved remains, its size was comparable to the large Metatheria Didelphodon. Recent phylogenetic analyses suggests that genus Altacreodus is a member of clade Ferae and the closest known sister taxon to order Hyaenodonta,Andreas Lang (2023.) "Analysis of functional morphology in carnassial dentitions (Carnivora, Dasyuromorphia, Hyaenodonta)". Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn. based on anatomy of its teeth. In some studies its position as a crown-group placental has been equivocal.