Bayer 04 Leverkusen, officially known as Bayer 04 Leverkusen Fußball GmbH (German: [ˌbaɪ̯ɐ ˈleːvɐˌkuːzn̩]) and commonly known as Bayer Leverkusen or simply Leverkusen, is a German professional football club based in Leverkusen, North Rhine-Westphalia. It competes in the Bundesliga, the top tier of German football, and plays its home matches at the BayArena.
Founded in 1904 by employees of the paint factory, today better known as a pharmaceutical company Bayer (whose headquarters are in Leverkusen and from which the club draws its name), the club was formerly a department of TSV Bayer 04 Leverkusen sports club whose members participate in athletics, gymnastics, basketball, field and handball.