Rafael Nadal defeated Ivan Ljubičić in the final, 3–6, 2–6, 6–3, 6–4, 7–6(7–3) to win the singles tennis title at the 2005 Madrid Open.[1] As of 2024, this remains his sole indoor hardcourt title.
Marat Safin was the reigning champion, but chose not to compete.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. All sixteen seeds received a bye into the second round.
Rafael Nadal (champion)
Andy Roddick (second round)
Nikolay Davydenko (third round)
Guillermo Coria (third round) David Nalbandian (semifinals) Mariano Puerta (third round) Gastón Gaudio (second round)
Ivan Ljubičić (final)
Thomas Johansson (third round)
Radek Štěpánek (quarterfinals) David Ferrer (quarterfinals) Mario Ančić (second round) Tommy Robredo (third round)
Dominik Hrbatý (third round)
Fernando González (quarterfinals) Robby Ginepri (semifinals) Juan Ignacio Chela (qualified).svg/1280px-Flag_of_Belgium_(civil).svg.png){kind=small}
Christophe Rochus (qualified)
Florent Serra (qualifying competition) Alberto Martín (qualified) Agustín Calleri (qualified) Tomáš Zíb (qualified)
Andreas Seppi (qualifying competition) Ivo Minář (first round) Jan Hernych (first round)
Nicolás Lapentti (first round) Ivo Karlović (qualified)
Răzvan Sabău (qualifying competition)