Rafael Nadal defeated Nicolas Kiefer in the final, 6–3, 6–2 to win the men's singles tennis title at the 2008 Canadian Open.
Novak Djokovic was the defending champion, but lost in the quarterfinals to Andy Murray.
The top eight seeds receive a bye into the second round.
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Roger Federer (second round)
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Novak Djokovic (quarterfinals)
Nikolay Davydenko (third round) David Ferrer (third round)
Andy Roddick (third round) James Blake (quarterfinals)
Andy Murray (semifinals) Stanislas Wawrinka (third round)
Richard Gasquet (quarterfinals)
Radek Štěpánek (first round) Tommy Robredo (second round) Fernando Verdasco (second round)
Fernando González (second round) Mikhail Youzhny (second round) Tomáš Berdych (second round)