1999–2000 LEN Champions League

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.