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
Key to colors in group tablesGroup winners and runners-up advanced to Final four
Blue Group
Red Group
Final Four (Naples)
Final standings
Team Splitska Banka Bečej Dynamo Moscow Posillipo
Dragan Rebić, Teo Đogaš, Petar Trumbić, Nikša Jaić, David Burburan, Roman Poláčik, Višeslav Sarić, Aleksandar Nagy, Samir Barać, Aljoša Kunac, Alen Bošković, Mario Oreb, Ivan KaturaHead coachDragan Matutinović
See also 1998–99 LEN Cup Winners' Cup 1998–99 LEN Cup