UFC 58: USA vs Canada was a mixed martial arts event held by the Ultimate Fighting Championship on March 4, 2006. It was held at the Mandalay Bay Events Center in Las Vegas, Nevada, and broadcast live on pay-per-view in the United States. In keeping with the theme of the card, each fight featured an American fighter against a Canadian fighter.

Preliminary card

Heavyweight bout
Icho Larenas vs Tom Murphy
Murphy defeats Larenas via a TKO in the third round at 1:59. Larenas was a late substitute for Christophe Midoux. This was a preliminary fight that did not air on the pay-per-view broadcast.

Light heavyweight bout
Rob MacDonald vs Jason Lambert
Lambert defeats MacDonald via a submission with a kimura in the first round at 1:54 . This was a preliminary fight that did not air on the pay-per-view broadcast.

Lightweight bout
Sam Stout vs Spencer Fisher
Stout defeats Fisher due to a split decision. Fisher was a late replacement for Kenny Florian, who injured during training for this fight. This was the UFC's first lightweight match since the division was suspended in 2004. This was a preliminary fight that did not air on the pay-per-view broadcast, though it did later air on an episode of UFC Unleashed on Spike TV.

Main card

Lightweight bout
Mark Hominick vs Yves Edwards
Hominick defeats Edwards via submission with a triangle armbar in the second round at 1:52.

Middleweight bout
Joe Doerksen vs Nathan Marquardt
Marquardt defeats Doerksen in an unanimous decision.

Welterweight bout
Georges St. Pierre vs B.J. Penn
St. Pierre defeats Penn in a split decision.

Middleweight bout
Steve Vigneault vs Mike Swick
Swick defeats Vigneault via submission with a guillotine choke in the first round at 2:09.

UFC Middleweight Championship
Rich Franklin (C) vs David Loiseau
Franklin defeats Loiseau in an unanimous decision and retains the UFC middleweight title. Franklin's hand broke but continued to fight until the end of the bout and ultimately won it. Judges scored the bout 50-42, 50-42, and 50-43