A checklist of the fishes of Ascension Island is presented. The speciesRhincodon typus,Alopias superciliosus,Isurus oxyrinchus,Carcharhinus obscurus,Galeocerdo cuvier,Sphyrna lewini,Hexanchus griseus,Manta birostris,Gymnothorax vicinus,Hippocampussp.,Epinephelus itajara,Cookeolus japonicus,Apogon pseudomaculatus,Phaeoptyx pigmentaria,Remora albescens,Caranx bartholomaei,Carangoides ruber,Decapterus tabl,Seriola dumerili,Thalassoma sanctaehelenae,Cryptotomussp.,Ruvettus pretiosus,Acanthocybium solandri,Auxis rochei,Auxis thazard,Euthynnus alletteratus,Katsuwonus pelamis,Thunnus alalunga,Thunnus obesus,Xiphias gladius,Istiophorus platypterus,Kajikia albida,Makaira nigricans,Tetrapturus pfluegeri,Hyperoglyphe perciformis,Schedophilussp.,Cantherhines macrocerus,Sphoeroides pachygasterandDiodon eydouxiiare recorded for the first time from Ascension Island. We have recognized two previous records as identification errors and indicate 11 other records as doubtful. Including the 40 new records, we now list 173 fish species from Ascension Island, of which 133 might be considered ‘coastal fish species’. Eleven of these (8.3%) appear to be endemic to the island and a further 16 species (12%) appear to be shared endemics with St Helena Island.