The genus Centroonoceras was proposed by Kobayashi (1934) for a Middle Ordovician cyrtoconic cephalopod from South Korea. The taxonomic position of Centroonoceras has remained ambiguous, however, due to insufficient documentation and illustration of its morphology. The type species, Centroonoceras tokunagai, was originally described by Kobayashi (1927) as a new taxon belonging to the family “Ooceratidae” of the order Oncocerida. When Kobayashi (1934) proposed Centroonoceras, he diagnosed the genus as an orthocerid cephalopod whose closest relationship was with Sactorthoceras Kobayashi, 1934. Flower (1946) later placed Centroonoceras in the family Sactorthoceratidae, an assignment followed by most subsequent workers, including Balashov and Zhuravleva (1962), Sweet (1964), and Chen and Zou (1984). Only Stait (1988) disagreed with Flower's assignment. He referred Centroonoceras to the family Proteoceratidae with the proviso that “this genus is extremely poorly known.” The purposes of the present report are 1) to clarify the generic concept of this enigmatic genus on the basis of the holotype of the type species and 2) to discuss its assignment.