The 2005–06 LEN Euroleague was the 43rd edition of LEN's premier competition for men's water polo clubs. It ran from 14 September 2005 to 20 May 2006, and it was contested by 36 teams. The Final Four (semifinals, final, and third place game) took place on May 19 and May 20 in Dubrovnik.

Posillipo

Honvéd

Mladost

Spandau

Jug

Vasas

Olympiacos

Marseille

Savona

Partizan

Ethnikos

Barcelona

Recco

Jadran

Šturm

Barceloneta

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Location of teams of the 2005–06 LEN Euroleague group stage.
Red: Group A; Green: Group B; Blue: Group C; Yellow: Group D.

Team	Pld	W	D	L	GF	GA	GD	Pts
Posillipo	6	5	0	1	60	48	+12	10
Honvéd	6	4	0	2	73	56	+17	8
HAVK Mladost	6	3	0	3	54	54	0	6
Spandau 04	6	0	0	6	47	78	−31	0

Team	Pld	W	D	L	GF	GA	GD	Pts
Jug Dubrovnik	6	5	0	1	73	52	+21	10
Vasas	6	3	1	2	57	58	−1	7
Olympiacos	6	2	1	3	54	61	−7	5
Marseille	6	1	0	5	56	69	−13	2

Team	Pld	W	D	L	GF	GA	GD	Pts
Savona	6	5	0	1	60	45	+15	10
Partizan	6	3	1	2	47	42	+5	7
Ethnikos Piraeus	6	2	0	4	53	56	−3	4
Barcelona	6	1	1	4	53	70	−17	3

Team	Pld	W	D	L	GF	GA	GD	Pts
Pro Recco	6	5	0	1	67	45	+22	10
Jadran Herceg Novi	6	3	0	3	54	57	−3	6
Šturm 2002	6	2	1	3	53	63	−10	5
Atlètic-Barceloneta	6	1	1	4	45	54	−9	3

The first legs were played on 22 March, and the second legs were played on 19 April 2006.

Team 1	Agg.Tooltip Aggregate score	Team 2	1st leg	2nd leg
Jadran Herceg Novi	15–15(1–4 p)	Posillipo	5–7	10–8
Partizan	14–16	Jug Dubrovnik	9–7	5–9
Pro Recco	23–15	Bp. Honvéd	11–8	12–7
Vasas	16–16(6–7 p)	Savona	6–5	10–9

Bazen u Gružu, Dubrovnik, Croatia

Semifinals 19 May 2006 Final 20 May 2006                       Savona 8       Jug Dubrovnik 9   Jug Dubrovnik 9       Pro Recco 7   Posillipo 8     Pro Recco (aet) 9   Third place           Savona 8     Posillipo 11

Final standings Team Jug Dubrovnik Pro Recco Posillipo Savona

2005–06 LEN Euroleague Champions
Jug Dubrovnik 3rd Cup

Final four MVP
Márton Szívós (Pro Recco)

• 2005–06 LEN Trophy