2004 Canada Masters – Singles

Roger Federer defeated the defending champion Andy Roddick in the final, 7–5, 6–3 to win the men's singles tennis title at the 2004 Canadian Open.

Seeds

 * 1)  Roger Federer (champion)
 * 2) 🇺🇸 Andy Roddick (final)
 * 3) 🇦🇷 Guillermo Coria (first round, retired due to a shoulder injury)
 * 4) 🇪🇸 Carlos Moyá (third round)
 * 5) 🇬🇧 Tim Henman (second round)
 * 6) 🇦🇷 David Nalbandian (first round)
 * 7) 🇪🇸 Juan Carlos Ferrero (first round, retired)
 * 8) 🇩🇪 Rainer Schüttler (first round)
 * 9) 🇦🇺 Lleyton Hewitt (third round)
 * 10) 🇺🇸 Andre Agassi (second round)
 * 11) 🇦🇷 Gastón Gaudio (first round)
 * 12) 🇫🇷 Sébastien Grosjean (first round)
 * 13)  Nicolás Massú (first round)
 * 14) 🇹🇭 Paradorn Srichaphan (second round)
 * 15) 🇷🇺 Marat Safin (first round)
 * 16) 🇦🇷 Juan Ignacio Chela (third round)

Qualifying seeds
• # 🇫🇷 Michaël Llodra (qualified)

• # 🇸🇰 Karol Beck (qualified)

• # 🇫🇷 Cyril Saulnier (qualifying competition, lucky loser)

• # 🇫🇷 Julien Benneteau (qualified)

• # 🇰🇷 Lee Hyung-taik (qualified)

• # Lu Yen-hsun (first round)

• # 🇸🇪 Thomas Johansson (qualifying competition, lucky loser)

• # 🇫🇷 Thierry Ascione (first round)

• # 🇨🇿 Jan Hernych (qualified)

• # 🇪🇨 Nicolás Lapentti (first round)

• # 🇺🇸 Alex Bogomolov Jr. (qualified)

• # 🇺🇸 Glenn Weiner (qualifying competition)

• # 🇦🇺 Todd Reid (qualified)

• # 🇮🇱 Harel Levy (qualifying competition)

• # 🇺🇸 Jeff Salzenstein (first round)

• # 🇫🇷 Julien Jeanpierre (qualifying competition)

Qualifiers
• # 🇫🇷 Michaël Llodra

• # 🇸🇰 Karol Beck

• # 🇺🇸 Alex Bogomolov Jr.

• # 🇫🇷 Julien Benneteau

• # 🇰🇷 Lee Hyung-taik

• # Michel Kratochvil

• # 🇨🇿 Jan Hernych

• # 🇦🇺 Todd Reid

Lucky losers
• # 🇫🇷 Cyril Saulnier

• # 🇸🇪 Thomas Johansson