The 2002–03 LEN Champions League was the 40th edition of LEN's premier competition for men's water polo clubs. It ran from 16 October 2002 to 17 May 2003, and it was contested by 29 teams. The Final Four (semifinals, final, and third place game) took place on May 16 and May 17 in Genoa.

Recco

Spandau

Barcelona

Partizan

Honvéd

Mladost

Nice

Olympiacos

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Location of teams of the 2002–03 LEN Champions League group stage.
Blue Group; Red Group.

Team	Pld	W	D	L	GF	GA	GD	Pts
Pro Recco	6	5	0	1	59	47	+12	10
Spandau 04	6	4	0	2	39	38	+1	8
Barcelona	6	2	1	3	44	44	0	5
Partizan	6	0	1	5	35	46	−11	1

Team	Pld	W	D	L	GF	GA	GD	Pts
Honvéd	6	5	1	0	58	44	+14	11
HAVK Mladost	6	3	1	2	48	44	+4	7
Olympic Nice	6	1	2	3	38	43	−5	4
Olympiacos	6	0	2	4	33	46	−13	2

Semifinals 16 May 2003 Final 17 May 2003                       Pro Recco 5       HAVK Mladost 4   Pro Recco 9       Honvéd 4   Honvéd 11     Spandau 04 6   Third place           HAVK Mladost 6     Spandau 04 5 Final standings Team Pro Recco Honvéd HAVK Mladost Spandau 04

2002–03 Champions League Champions  Pro Recco 3rd title Jesús Rollán, Alberto Angelini, Luca Giustolisi, Danilo Ikodinović, Simone Mina, Vladimir Vujasinović, Daniele Bettini, Tibor Benedek, Paolo Petronelli, Alessandro Calcaterra, Massimiliano Ferretti, Alessandro Caliogna, Alberto Ghibellini Head coach Marco Baldineti

• 2002–03 LEN Cup Winners' Cup
• 2002–03 LEN Cup