- The taxonomy of European species of Coitus (Cottidae) is revised. Results of molecular studies are summarised and the variability of morphological characters is reviewed. Molecular and morphological data support the recognition of 15 diagnosable species in Europe. A neotype is designated for C. gobio; the type locality is in the lower Elbe drainage. Coitus gobio, C. hispaniolensis, C. koshewnikowi, C. microstomus, C. petiti, and C. poecilopus are re-diagnosed. Eight new species are described. Three of them are restricted to France: C. aturi to the Adam drainage, C. duranii to the upper Dordogne, upper Lot and upper Loire drainages, and C. rondeleti to the Herault drainage. Two new species are described from the Atlantic and North Sea basins: C. perifretum from Great Britain, and the ScheIdt, Rhine, Seine, lower Loire and lower Garonne drainages, and C. rhenanus from the Meuse and lower and middle Rhine drainages. Coitus scatul'igo is described from a single spring in northeastern Italy. In the Danube drainage, C. mctae front the upper Save and C. transsilvaniae from the upper Arges are distinguished from the widespread C. gobio. Lectotypes are designated for C. ferrugineus and C. pellegrini. Coitus kosllewnikowi Gratzianow, 1907 is declared nomel1 protectum and C. gobio microcephalus Kessler, 1868 is declared nomen oblitum. The original spelling of C. milvensis is discussed.