Rafael Nadal defeated Andre Agassi in the final, 6–3, 4–6, 6–2 to win the men's singles tennis title at the 2005 Canadian Open. Roger Federer was the reigning champion, but did not participate this year.

Seeds

• # 🇪🇸 Rafael Nadal (champion) • # 🇦🇺 Lleyton Hewitt (first round, retired due to illness) • # 🇺🇸 Andy Roddick (first round) • # 🇺🇸 Andre Agassi (final) • # 🇷🇺 Nikolay Davydenko (third round) • # 🇦🇷 Gastón Gaudio (quarterfinals) • # 🇦🇷 Guillermo Coria (first round) • # 🇦🇷 Mariano Puerta (quarterfinals) • # 🇦🇷 David Nalbandian (second round) • # 🇬🇧 Tim Henman (first round) • # 🇪🇸 Tommy Robredo (third round) • # 🇸🇪 Thomas Johansson (second round) • # Ivan Ljubičić (first round) • # 🇨🇿 Radek Štěpánek (first round) • # 🇫🇷 Richard Gasquet (second round) • # Fernando González (first round)

Draw

Finals

Top half

Section 1

Section 2

Bottom half

Section 3

Section 4

Qualifying

Seeds

• # 🇨🇿 Tomáš Zíb (qualifying competition) • # 🇮🇹 Davide Sanguinetti (qualified) • # Stanislas Wawrinka (qualified) • # 🇱🇺 Gilles Müller (qualifying competition) • # 🇮🇹 Andreas Seppi (first round) • # 🇫🇷 Michaël Llodra (first round) • # 🇦🇺 Wayne Arthurs (first round) • # 🇺🇸 Kevin Kim (qualified) • # 🇪🇨 Nicolás Lapentti (qualifying competition) • # 🇫🇷 Florent Serra (qualified) • # 🇨🇿 Jan Hernych (first round) • # Novak Djokovic (qualifying competition) • # 🇺🇸 Justin Gimelstob (first round) • # 🇸🇪 Jonas Björkman (qualified) • # Jean-Rene Lisnard (first round) • # 🇫🇷 Arnaud Clément (qualified)

Qualifiers

• # 🇫🇷 Arnaud Clément • # 🇮🇹 Davide Sanguinetti • # Stanislas Wawrinka • # 🇸🇪 Jonas Björkman • # 🇮🇱 Noam Okun • # 🇫🇷 Nicolas Mahut • # 🇫🇷 Florent Serra • # 🇺🇸 Kevin Kim

Draw

First qualifier

Second qualifier

Third qualifier

Fourth qualifier

Fifth qualifier

Sixth qualifier

Seventh qualifier

Eighth qualifier