TYPE SPECIES:
• C. medius Owen, 1842 [nomen conservandum]
  OTHER SPECIES:
• ?C. mogrebiensis de Lapparent, 1955
• C. oxonensis Phillips, 1871
• C. phillipsi Sauvage, 1880 [nomen nudum]
  
  MISASSIGNED SPECIES:
• C. brachyurus Owen, 1842 [nomen dubium] "short-tailed whale lizard" == Iguanodon atherfieldensis
• C. brevis Owen, 1842 [nomen dubium] "short whale lizard" == Pelorosaurus conybearei == Iguanodon anglicus
• "C." conybearei Melville, 1849 ?» Brachiosauridae
• C. epioolithicus Owen, 1842 [nomen oblitum] "after the Oolite whale lizard" == Cetiosauriscus longus
• C. glymptonensis Phillips, 1871 [nomen dubium?] = Cetiosauriscus glymptonensis
• C. greppini (von Huene, 1922) [nomen dubium?] (originally Ornithopsis) = Cetiosauriscus greppini
• C. humerocristatus Hulke, 1874 [nomen dubium] "whale lizard with a crested humerus" = Pelorosaurus humerocristatus
• C. hypoolithicus Owen & Anonymous, 1841 [nomen oblitum] "under the Oolite whale lizard" == C. medius
• C. leedsi (von Huene & Woodward, 1905) (originally Cetiosauriscus) == C. stewarti
• C. leedsii (Hulke, 1887) [nomen dubium] (originally Ornithopsis) = Pelorosaurus leedsii
• C. longus Owen, 1842 [nomen dubium?] "long whale lizard" = Cetiosauriscus longus
• "C." rigauxi Sauvage, 1874 [nomen dubium] » incertae sedis
• C. rugulosus (Owen, 1841) [nomen dubium] (originally Cardiodon) = Cardiodon rugulosus

Animalia
Vertebrata
Tetrapoda
Sauropsida
Archosauromorpha
Ornithodira
Dinosauria
Sauropodomorpha
Sauropoda

Owen originally considered Cetiosaurus to be a crocodile-like creature, and thus did not include it in the original description of the taxon Dinosauria, which he published the same year as C. medius.