The history of the enteroviruses is described, and how poliovirus came to be recognized as the prototype species of the genus, a subdivision of the family Picornaviridae. Albert Sabin was one of the main contributors. He isolated several enterovirus types and established them as causative agents of human disease. The enteroviruses were discovered only after new methods were introduced for working with viruses. They are now recognized as constituting one of the genera of the picornavirus family. Pico-rna-virus stands for viruses which are small (pico), and have an RNA genome. The enterovirus genus includes the polioviruses, the coxsackieviruses and the echoviruses of humans, plus a number of enteroviruses of lower animals (e.g., monkeys, cattle, pigs, mice). Over 100 serotypes are now recognized, the first having been the polioviruses.