The systematics and taxonomy of the large allosauroid Carcharodontosaurus are reviewed and a new species of this theropod is described from the Late Cretaceous (Cenomanian) Echkar Formation of Niger, which is roughly coeval with Cenomanian beds elsewhere in northern Africa. The type species, C. saharicus, was based originally on a pair of isolated teeth from Algeria, to which was referred a partial skull and skeleton from Egypt. All of this material was either lost or destroyed more than 50 years ago. Thus, a neotype is designated for C. saharicus, a well-preserved cranium from the Kem Kem beds in Morocco. Newly discovered material from Niger is distinct from that of C. saharicus, justifying the erection of a distinct southern species. C. iguidensis, n. sp. is represented by cranial (maxilla, braincase, dentary, lacrimal, teeth) and postcranial (vertebrae) remains and grew to the same large body size as C. saharicus. The skull displays several autapomorphies, including a laterally reduced external antorbital fossa, a maxillary anteromedial process that is broadly arched toward the midline, a prominent horizontal crest on the medial aspect of the maxilla, and a deeply invaginated fossa on the laterosphenoid. Unlike C. saharicus the ventral rim of the external antorbital fossa does not protrude laterally, the anteromedial process does not demarcate a deep ventral fossa, and the frontal-lacrimal suture is not elevated. The new material provides evidence of differentiation among Cenomanian-age faunas from the Sahara and supports a close relationship between Carcharodontosaurus, Giganotosaurus, and Acrocanthosaurus.