Otoliths of 10 new species, including nine Gadidae from different localities in the North Sea Basin (Middle Oligocene — Upper Pliocene) are described: Gadus parallelus, Trisopterus concavus, T. incognitus, Colliolus parvus, C. johannettae, C. schwarzhansi, Palaeoraniceps regularis, Molva primaeva, Brosme heinrichi and ? Macruridarum deurnensis. Three new genera are established: Protocolliolus, Neocolliolus and Palaeoraniceps. Type material of some fossil otoliths of Gadidae described by Koken (1884, 1891) has been studied; as a result some systematic errors are corrected. The existence of two recent species of coal-fishes (Pollachius virens (L.) and Pollachius carbonarius (L.)) is ascertained by study of their otoliths.