In this paper, a shark-bitten partial tibiotarsus of a hesperornithiform bird is described from the Upper Cretaceous of Grant County, South Dakota, U.S.A. Whether the bite marks represent a predatory attack or scavenging is uncertain, but they are attributed to an anacoracid shark, Squalicorax cf. S. falcatus. The specimen is significant because it further indicates that hesperornithiform birds were common food sources for carnivores in the Late Cretaceous Western Interior Seaway of North America, and that Squalicorax was a trophic generalist.