Richard Owen named the genus for a now-lost tooth, part of the collection of naturalist Joseph Chaning Pearce, found near Bradford-on-Avon, but did not assign it a specific name at the time. The generic name is derived from Greek καρδία, "kardia", "heart", and ὀδών, "odon", "tooth", in reference to its heart-shaped profile. A few years later, in 1844, he added the specific name "rugulosus", meaning "wrinkled" in Latin. "Cardiodon" was the first sauropod given a formal name to, though Owen was at the time completely unaware of the sauropod nature of the find.