| Sieg | 26-2 | Michael Bisping  | Technical Submission (rear-naked choke) |  | UFC 217: Bisping vs St. Pierre | Nov 04, 2017 | 3 | 4:23 | New York City, New York, United States  |
| Sieg | 25-2 | Johny Hendricks | Decision (split) |  | UFC 167: St. Pierre vs Hendricks | Nov 16, 2013 | 5 | 5:00 | Las Vegas, United States |
| Sieg | 24-2 | Nick Diaz | Decision (unanimous) |  | UFC 158: St.Pierre vs Diaz | Mar 16, 2013 | 5 | 5:00 | Montreal, Canada  |
| Sieg | 23-2 | Carlos Condit | Decision (unanimous) | | UFC 154 | Nov 17, 2012 | 5 | 5:00 | Montreal, Quebec, Canada |
| Sieg | 22-2 | Jake Shields | Decision (unanimous) |  | UFC 129 | Apr 30, 2011 | 5 | 5:00 | Toronto, Ontario, Canada |
| Sieg | 21-2 | Josh Koscheck | Decision (unanimous) |  | UFC 124 | Dec 11, 2010 | 5 | 5:00 | Montreal, Quebec, Canada |
| Sieg | 20-2 | Dan Hardy | Decision (unanimous) |  | UFC 111 | Mar 27, 2010 | 5 | 5:00 | Newark, United States |
| Sieg | 19-2 | Thiago Alves  | Decision (unanimous) |  | UFC 100 | Jul 11, 2009 | 5 | 5:00 | Las Vegas, United States |
| Sieg | 18-2 | B.J. Penn | TKO (corner stoppage) |  | UFC 94 | Jan 31, 2009 | 4 | 5:00 | Las Vegas, United States |
| Sieg | 17-2 | Jon Fitch | Decision (unanimous) |  | UFC 87 | Aug 09, 2008 | 5 | 5:00 | Minneapolis, United States |
| Sieg | 16-2 | Matt Serra | TKO (knees to the body) |  | UFC 83 | Apr 19, 2008 | 2 | 4:45 | Montreal, Quebec, Canada |
| Sieg | 15-2 | Matt Hughes | Submission (armbar) |  | UFC 79 | Dec 29, 2007 | 2 | 4:54 | Las Vegas, United States |
| Sieg | 14-2 | Josh Koscheck | Decision (unanimous) |  | UFC 74 | Aug 25, 2007 | 3 | 5:00 | Las Vegas, United States |
| Niederlage | 13-2 | Matt Serra | TKO (punches) |  | UFC 69 | Apr 07, 2007 | 1 | 3:25 | Houston, United States |
| Sieg | 13-1 | Matt Hughes | TKO (head kick & punches) |  | UFC 65 | Nov 18, 2006 | 2 | 1:25 | Sacramento, United States |
| Sieg | 12-1 | B.J. Penn | Decision (split) |  | UFC 58 | Mar 04, 2006 | 3 | 5:00 | Las Vegas, United States |
| Sieg | 11-1 | Sean Sherk | TKO (punches & elbows) |  | UFC 56 | Nov 19, 2005 | 2 | 2:53 | Las Vegas, United States |
| Sieg | 10-1 | Frank Trigg | Submission (rear-naked choke) |  | UFC 54 | Aug 20, 2005 | 1 | 4:09 | Las Vegas, United States |
| Sieg | 9-1 | Jason Miller | Decision (unanimous) |  | UFC 52 | Apr 16, 2005 | 3 | 5:00 | Las Vegas, United States |
| Sieg | 8-1 | Dave Strasser | Submission (kimura) | | TKO 19: Rage | Jan 29, 2005 | 1 | 1:52 | Montreal, Quebec, Canada |
| Niederlage | 7-1 | Matt Hughes | Submission (armbar) |  | UFC 50 | Oct 22, 2004 | 1 | 4:59 | Atlantic City, United States |
| Sieg | 7-0 | Jay Hieron | TKO (punches) | | UFC 48 | Jun 19, 2004 | 1 | 1:42 | Las Vegas, United States |
| Sieg | 6-0 | Karo Parisyan | Decision (unanimous) |  | UFC 46 | Jan 31, 2004 | 3 | 5:00 | Las Vegas, United States |
| Sieg | 5-0 | Pete Spratt | Submission (rear naked choke) | | TKO14: Road Warriors | Nov 29, 2003 | 1 | 3:40 | Victoriaville, Quebec, Canada |
| Sieg | 4-0 | Thomas Denny | TKO (cut) | | UCC 12: Adrenaline | Jan 25, 2003 | 2 | 4:45 | Montreal, Quebec, Canada |
| Sieg | 3-0 | Travis Galbraith | TKO (elbows) | | UCC11:The Next Level | Oct 11, 2002 | 1 | 2:03 | Montreal, Quebec, Canada |
| Sieg | 2-0 | Justin Bruckmann | Submission (armbar) | | UCC10: Battles | Jun 15, 2002 | 1 | 3:53 | Gatineau, Quebec, Canada |
| Sieg | 1-0 | Ivan Menjivar | TKO (punches) | | UCC7: Bad Boyz | Jan 25, 2002 | 1 | 4:59 | Montreal, Quebec, Canada |
