2004–05 LEN Euroleague

The 2004–05 LEN Euroleague was the 42nd edition of LEN's premier competition for men's water polo clubs. It ran from 29 September 2004 to 21 May 2005, and it was contested by thirty five teams from fifteen countries. CN Posillipo defeated defending champion Budapest Honvéd in the final to win its third title, while Pro Recco was third and Jug Dubrovnik fourth.

Quarter-finals
The first legs were played on 30 March, and the second legs were played on 20 April 2005.

Final Four
Piscina Felice Scandone, Naples, Italy.