The 1999–2000 LEN Champions League was the 37th edition of LEN's premier competition for men's water polo clubs. It ran from 27 October 1999 to 27 May 2000, and it was contested by 28 teams. The Final Four (semifinals, final, and third place game) took place on May 26 and May 27 in Bečej.
Preliminary round
Key to colors in group tablesGroup winners and runners-up advanced to Final four
Blue Group
Red Group
Final Four (Bečej)
Final standings
Team Bečej HAVK Mladost BVSC POŠK
Aleksandar Šoštar, Predrag Zimonjić, Slobodan Soro, Goran Krstonošić, Nenad Vukanić, Branko Peković, Aleksandar Ćirić, Veljko Uskoković, László Tóth, Aleksandar Šapić, Jugoslav Vasović, Balázs Vincze, Nebojša MilićHead coachZoltán Kásás
See also 1999–00 LEN Cup Winners' Cup 1999–00 LEN Cup