Issues of purity are central to modern sport, as well as to modernity in general. This chapter discusses the role of purity in modern sport by also including its counterpart and hybridity. It argues that while modern sport strives to minimize non-human impact, it acknowledges the hybrid material that sport results are moulded from. The chapter discusses purity in modern sport as an ontological issue. From a science and technology studies perspective, sport studies’ understanding of modern sport as a set of formalized, physical contests among human beings could be approached in many ways. If science aims to produce truths and facts about the properties of natural objects, modern sport aims to produce results, which reveal something about human performance and properties. In any event, modern sport alludes to the scientifically experimental method of producing a distilled form of pure nature, without retaining the claim that the moderns differ totally from our predecessors.