Bayer 04 Leverkusen Fußball GmbH, also known as Bayer 04 Leverkusen [ˌbaɪ̯ɐ ˈleːvɐˌkuːzn̩], Bayer Leverkusen, Leverkusen or simply Bayer, is a German football club based in Leverkusen, North Rhine-Westphalia.
The club plays in the Bundesliga, the top tier of the German football league system, and host matches at the BayArena.
Bayer Leverkusen have won one DFB-Pokal and one UEFA Cup. Their local rivals are 1. FC Köln.