The theropod genus and species Ornithomimus velox was erected based on a partial hind limb recovered from the late Maastrichtian Denver Formation. A partial manus, which likely belonged to the same individual, was also recovered and described in the same paper. Ornithomimus edmontonicus is the only other valid species currently recognized in the genus. The validity of Ornithomimus velox has been questioned due to its fragmentary nature and because the diagnostic features identified when the species was erected are now considered characteristic for the family. The pes and manus of Ornithomimus velox were never fully prepared. In the original description, reconstructed metatarsals were figured, but manual phalanges, although preserved, were not described. Here we describe and reevaluate Ornithomimus velox based upon a new preparation of the specimen. Metacarpal proportions are diagnostic for the genus, with metacarpal I longer than metacarpal II, which in turn is longer than metacarpal III. The pes and manus of Ornithomimus velox are smaller than in the type specimen of Ornithomimus edmontonicus. Ornithomimus velox can be distinguished from Ornithomimus edmontonicus based on the robusticity of the pes. Material previously referred to Ornithomimus velox from the Kaiparowits Formation of Utah is older and morphologically distinct and does not represent the same species. The morphological disparity and temporal separation observed in specimens referred to Ornithomimus edmontonicus suggest that it may represent a species complex. The redescription and diagnosis of Ornithomimus velox provides a new framework to investigate ornithomimid systematics.