| Doubles | |
|---|---|
| 2003 Western & Southern Financial Group Masters | |
| Champions |  Bob Bryan Mike Bryan |
| Runners-up |  Wayne Arthurs Paul Hanley |
| Final score | 7–5, 7–6(7–5) |
James Blake and Todd Martin were the defending champions but lost in the second round to Wayne Arthurs and Paul Hanley.
Bob Bryan and Mike Bryan won in the final 7–5, 7–6(7–5) against Arthurs and Hanley.
All eight seeded teams received byes to the second round.
Mahesh Bhupathi / 
Max Mirnyi (semifinals) Bob Bryan / Mike Bryan (champions)
Mark Knowles / 
Daniel Nestor (semifinals)
Jonas Björkman / Todd Woodbridge (quarterfinals) Leander Paes / 
David Rikl (second round)
Michaël Llodra / Fabrice Santoro (quarterfinals) Wayne Arthurs / Paul Hanley (final) Martin Damm / Cyril Suk (quarterfinals)| Semifinals | Final | ||||||||||||
| 1 | 5 | 77 | 3 | ||||||||||
| 7 | 7 | 65 | 6 | ||||||||||
| 7 | 5 | 65 | |||||||||||
| 2 | 7 | 77 | |||||||||||
| 3 | 2 | 3 | |||||||||||
| 2 | 6 | 6 | |||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | 6 | 3 | 6 | ||||||||||||||||||||||||
| 3 | 7 | 7 | 3 | 6 | 1 | ||||||||||||||||||||||
| 6 | 5 | 5 | 1 | 77 | 6 | ||||||||||||||||||||||
| 3 | 5 | 8 | 64 | 4 | |||||||||||||||||||||||
| 6 | 7 | ||||||||||||||||||||||||||
| 8 | w/o | ||||||||||||||||||||||||||
| 1 | 5 | 77 | 3 | ||||||||||||||||||||||||
| 7 | 7 | 65 | 6 | ||||||||||||||||||||||||
| 4 | 6 | 1 | 6 | ||||||||||||||||||||||||
| 78 | 6 | 1 | 6 | 2 | |||||||||||||||||||||||
| 66 | 4 | 4 | 63 | 6 | 3 | ||||||||||||||||||||||
| 3 | 4 | 7 | 77 | 4 | 6 | ||||||||||||||||||||||
| WC | 6 | 6 | WC | 4 | 5 | ||||||||||||||||||||||
| 7 | 6 | 7 | |||||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 6 | w/o | ||||||||||||||||||||||||||
| 3 | 5 | Alt | |||||||||||||||||||||||||
| Alt | 6 | 7 | 6 | 6 | 1 | 1 | |||||||||||||||||||||
| 3 | 5 | 3 | 4 | 6 | 6 | ||||||||||||||||||||||
| 6 | 7 | 2 | 4 | ||||||||||||||||||||||||
| 3 | 6 | 6 | |||||||||||||||||||||||||
| 3 | 2 | 3 | |||||||||||||||||||||||||
| 2 | 6 | 6 | |||||||||||||||||||||||||
| 5 | 63 | 4 | |||||||||||||||||||||||||
| 6 | 5 | 6 | 77 | 6 | |||||||||||||||||||||||
| 4 | 7 | 0 | 1 | 4 | |||||||||||||||||||||||
| 6 | 1 | 78 | 2 | 6 | 6 | ||||||||||||||||||||||
| WC | 4 | 6 | 66 | 3 | 2 | ||||||||||||||||||||||
| 2 | 6 | 6 | |||||||||||||||||||||||||
Bob and Mike Bryan were the defending champions, but lost in the third round to Leoš Friedl and Mikhail Youzhny.
Xavier Malisse and Olivier Rochus were the defending champions, but lost in the third round against third seeds and eventual finalists Bob & Mike Bryan.
Michaël Llodra and Fabrice Santoro were the defending champions, but they lost in quarterfinals 6–7(2), 5–7, against Jonas Björkman and Max Mirnyi.
Bob and Mike Bryan were the defending champions, they lost to sixth-seeded Michaël Llodra and Fabrice Santoro in the semifinals.
Mahesh Bhupathi and Leander Paes were the defending champions. They were both present but did not compete together.
Bhupathi partnered with Martin Damm, but lost in the quarterfinals to Wayne Black and Kevin Ullyett.
Paes partnered with Nenad Zimonjić, but lost in the second round to Jonathan Erlich and Andy Ram.
Paul Haarhuis and Yevgeny Kafelnikov were defending champions, but they lost in the final to third seeds Bob and Mike Bryan, who won the first Grand Slam title of their careers.
The 2003 Canada Masters doubles was the men's doubles event of the one hundred and fourteenth edition of the Canada Masters; a WTA Tier I tournament and the most prestigious men's tennis tournament held in Canada. Bob Bryan and Mike Bryan were the defending champions but lost in the semifinals to Jonas Björkman and Todd Woodbridge. Mahesh Bhupathi and Max Mirnyi won in the final 6–3, 7–6(7–4) against Björkman and Woodbridge.
Michaël Llodra and Fabrice Santoro were the defending champions, and won the final 7–6(4), 6–3 against Bob and Mike Bryan.
Paul Hanley and Nathan Healey were the defending champions but they competed with different partners that year, Hanley with Wayne Arthurs and Healey with Jordan Kerr.
Wayne Ferreira and Yevgeny Kafelnikov were the defending champions but did not compete that year.
Roger Federer and Max Mirnyi were the defending champions but only Mirnyi competed that year with Mahesh Bhupathi.
Bob Bryan and Mike Bryan were the defending champions and successfully defended their title, defeating Jonas Björkman and Max Mirnyi 7–6(11–9), 7–6(7–4) in the final.
Arnaud Clément and Sébastien Grosjean were the defending champions, but did not partner together this year. Clément partnered Jaroslav Levinský, losing in the first round. Grosjean partnered Gaël Monfils, losing in the second round.
Mark Knowles and Daniel Nestor were the defending champions, but lost in the first round to Paul Goldstein and Jim Thomas.
Mahesh Bhupathi and Max Mirnyi were the defending champions, but lost in the quarterfinals to Michaël Llodra and Fabrice Santoro.
Mark Knowles and Daniel Nestor were the defending champions, but lost in Quarterfinals to Wayne Black and Kevin Ullyett.
Wayne Black and Kevin Ullyett were the defending champions, but lost in second round to Mario Ančić and Ivan Ljubičić.
Mark Knowles and Daniel Nestor were the defending champions, but lost in semifinals to Jonas Björkman and Max Mirnyi.
Mahesh Bhupathi and Max Mirnyi were the defending champions, but played this tournament with different partners. Bhupathi teamed up with Todd Woodbridge while Mirnyi teamed up with Jonas Björkman. Both pairs were eliminated in semifinals.
Mahesh Bhupathi and Max Mirnyi defeated defending champions Wayne Arthurs and Paul Hanley 2–6, 6–3, 6–4 in the final. It was the 34th title for Bhupathi and the 20th title for Mirnyi in their respective careers.
