The 1998–99 LEN Champions League was the 36th edition of LEN's premier competition for men's water polo clubs. It ran from 1998 to 5 June 1999, and it was contested by 16 teams. The Final Four (semifinals, final, and third place game) took place on June 4 and June 5 in Naples.
Preliminary round
Blue Group
Red Group
Final Four (Naples)
See also
- 1998–99 LEN Cup Winners' Cup
- 1998–99 LEN Cup
