| Men's doubles | |
|---|---|
| 2004 Estoril Open | |
| Champions |  Juan Ignacio Chela Gastón Gaudio |
| Runners-up |  František Čermák Leoš Friedl |
| Score | 6–2, 6–1 |
Mahesh Bhupathi and Max Mirnyi were the defending champions but did not compete that year.
Juan Ignacio Chela and Gastón Gaudio won in the final 6–2, 6–1 against František Čermák and Leoš Friedl.
František Čermák / Leoš Friedl (final)
Massimo Bertolini / 
Robbie Koenig (quarterfinals) Petr Pála / Radek Štěpánek (first round)
Scott Humphries / Jared Palmer (first round)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | F Čermák L Friedl | 77 | 7 | ||||||||||||||||||||||||
 I Labadze  M Safin | 62 | 5 | 1 | F Čermák L Friedl | 6 | 6 | |||||||||||||||||||||
| B Ulihrach J Vaněk | 4 | 1 | WC |  F Gil B Mota | 4 | 3 | |||||||||||||||||||||
| WC | F Gil B Mota | 6 | 6 | 1 | F Čermák L Friedl | 4 | 6 | 6 | |||||||||||||||||||
| 3 | P Pála R Štěpánek | 4 | 0 | L Arnold A Calleri | 6 | 4 | 2 | ||||||||||||||||||||
| G Cañas M Zabaleta | 6 | 6 | G Cañas M Zabaleta | 4 | 0 | ||||||||||||||||||||||
| L Arnold A Calleri | 6 | 6 | L Arnold A Calleri | 6 | 6 | ||||||||||||||||||||||
 F Mayer R Schüttler | 2 | 1 | 1 | F Čermák L Friedl | 2 | 1 | |||||||||||||||||||||
P Luxa  R Wassen | 4 | 1 | J I Chela G Gaudio | 6 | 6 | ||||||||||||||||||||||
| T Cibulec D Škoch | 6 | 6 | T Cibulec D Škoch | 6 | 6 | ||||||||||||||||||||||
| WC | T Godinho L Tavares | 6 | 2 | 77 | WC | T Godinho L Tavares | 1 | 2 | |||||||||||||||||||
| 4 | S Humphries J Palmer | 3 | 6 | 65 | T Cibulec D Škoch | 6 | 2 | 4 | |||||||||||||||||||
 G Carraz F Santoro | 1 | 4 | J I Chela G Gaudio | 4 | 6 | 6 | |||||||||||||||||||||
| J I Chela G Gaudio | 6 | 6 | J I Chela G Gaudio | 6 | 6 | ||||||||||||||||||||||
| J Hernych T Zíb | 1 | 1 | 2 | M Bertolini R Koenig | 4 | 4 | |||||||||||||||||||||
| 2 | M Bertolini R Koenig | 6 | 6 | ||||||||||||||||||||||||
František Čermák and Leoš Friedl were the defending champions, but Čermák chose not to participate, and only Friedl competed that year.
Friedl partnered with Michael Kohlmann, but lost in the quarterfinals to Jordan Kerr and David Škoch.
Mariusz Fyrstenberg and Marcin Matkowski were the defending champions, but lost in the semifinals to František Čermák and Leoš Friedl.
Paul Hanley and Nathan Healey were the defending champions but only Healey competed that year with Jeff Coetzee.
Tomás Carbonell and Daniel Orsanic were the defending champions but did not compete that year.
Mahesh Bhupathi and Leander Paes were the defending champions but they competed with different partners that year, Bhupathi with Todd Woodbridge and Paes with David Rikl.
Gastón Etlis and Martín Rodríguez were the defending champions but lost in the first round to Agustín Calleri and Mariano Hood.
Stephen Huss and Myles Wakefield were the defending champions but did not compete that year.
Joshua Eagle and David Rikl were the defending champions but Eagle chose not to compete this year. Rikl instead competed with Leander Paes.
František Čermák and Leoš Friedl were the defending champions but lost in the final 6–4, 6–7 (7–9), 6–3 against Mariusz Fyrstenberg and Marcin Matkowski.
Lucas Arnold and Luis Lobo were the defending champions but only Arnold competed that year with Mariano Hood.
Juan Ignacio Chela and Gastón Gaudio were the defending champions. Chela participated with Tommy Robredo this year, finishing runner-up. Gaudio did not participate this year.
Enzo Artoni and Fernando Vicente were the defending champions. Artoni partnered with Marcin Matkowski this year, losing in the quarterfinals. Vicente did not participate.
Leander Paes and David Rikl were the two-time defending champions, but did not participate this year. Rikl was also the three-time defending champion, having won the title with Joshua Eagle in 2002.
František Čermák and Leoš Friedl were the defending champions, but lost in the semifinals to eventual champions Jiří Novák and Andrei Pavel.
David Ferrer and Santiago Ventura were the defending champions, but Ferrer did not participate this year. Ventura partnered with Flávio Saretta, losing in the first round.
František Čermák and Leoš Friedl were the defending champions, but Čermák did not participate this year. Friedl partnered Michael Kohlmann, losing in the first round.
František Čermák and Leoš Friedl were the defending champions.
Lucas Arnold and Mariano Hood were the defending champions, but lost in the semifinals this year.
Leoš Friedl and Andrei Pavel were the defending champions, but chose not to participate together. Friedl played alongside František Čermák, but lost in the first round to Juan Ignacio Chela and Luis Horna. Pavel teamed up with Rogier Wassen, but lost in the first round to Tomáš Cibulec and Łukasz Kubot.
František Čermák and Leoš Friedl were the defending champions, but Čermák did not compete this year. Friedl teamed up with Andrei Pavel and successfully defended his title, by defeating Christophe Rochus and Olivier Rochus 6–2, 6–7(5–7), 6–0 in the final.