Patrick Rafter defeated Richard Krajicek in the final, 7–6,(7–3), 6–4 to win the men's singles tennis title at the 1998 Canadian Open. Rafter became the first tennis player in 10 years in winning the tournament without dropping a set, after Ivan Lendl did the same achievement in 1988. Chris Woodruff was the reigning champion, but did not participate this year due to an 8-month injury.

Seeds

A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. The top eight seeds received a bye to the second round.

Draw

Finals

Top half

Section 1

Section 2

Bottom half

Section 3

Section 4

Qualifying

Qualifying seeds

• # 🇮🇹 Laurence Tieleman (qualified) • # 🇺🇸 Alex O'Brien (qualifying competition, retired, lucky loser) • # 🇺🇸 Brian MacPhie (qualified) • # Neville Godwin (qualified) • # 🇫🇮 Tuomas Ketola (qualifying competition, lucky loser) • # 🇪🇸 Óscar Burrieza (qualifying competition) • # Cecil Mamiit (qualified) • # 🇫🇷 Olivier Delaître (first round) • # David Nainkin (qualified) • # 🇺🇸 Doug Flach (qualified) • # 🇺🇸 David Witt (first round) • # 🇧🇾 Max Mirnyi (qualifying competition) • # 🇺🇸 Michael Russell (qualified) • # Ronald Agénor (qualifying competition)

Qualifiers

• # 🇮🇹 Laurence Tieleman • # 🇺🇸 Brian MacPhie • # Neville Godwin • # 🇺🇸 Doug Flach • # David Nainkin • # Cecil Mamiit • # 🇺🇸 Michael Russell

Lucky losers

• # 🇺🇸 Alex O'Brien • # 🇫🇮 Tuomas Ketola

Qualifying draw

First qualifier

Second qualifier

Third qualifier

Fourth qualifier

Fifth qualifier

Sixth qualifier

Seventh qualifier