| Niederlage | 45-9 | Josh Koscheck  | KO (punches) |  | UFC 135 | Sep 24, 2011 | 1 | 4:59 | Denver, Colorado, US |
| Niederlage | 45-8 | B.J. Penn | KO (punches) |  | UFC 123 | Nov 20, 2010 | 1 | 0:21 | Auburn Hills, Michigan, US |
| Sieg | 45-7 | Ricardo Almeida | Technical Submission (anaconda choke) |  | UFC 117 | Aug 07, 2010 | 1 | 3:15 | Oakland, California, United States |
| Sieg | 44-7 | Renzo Gracie  | TKO (leg kicks and punches) |  | UFC 112 | Apr 10, 2010 | 3 | 4:40 | Abu Dhabi, United Arab Emirates |
| Sieg | 43-7 | Matt Serra | Decision (unanimous) |  | UFC 98 | May 23, 2009 | 3 | 5:00 | Las Vegas, Nevada, United States |
| Niederlage | 42-7 | Thiago Alves | TKO (flying knee and punches) |  | UFC 85 | Jun 07, 2008 | 2 | 1:02 | London, England |
| Niederlage | 42-6 | Georges St. Pierre  | Submission (armbar) |  | UFC 79 | Dec 29, 2007 | 2 | 4:54 | Las Vegas, United States |
| Sieg | 42-5 | Chris Lytle | Decision (unanimous) | | UFC 68 | Mar 03, 2007 | 3 | 5:00 | Columbus, Ohio, United States |
| Niederlage | 41-5 | Georges St. Pierre | TKO (head kick & punches) |  | UFC 65 | Nov 18, 2006 | 2 | 1:25 | Sacramento, United States |
| Sieg | 41-4 | B.J. Penn | TKO (punches) |  | UFC 63 | Sep 23, 2006 | 3 | 3:53 | Anaheim, California, US |
| Sieg | 40-4 | Royce Gracie | TKO (punches) | | UFC 60 | May 27, 2006 | 1 | 4:39 | Los Angeles, California, United States |
| Sieg | 39-4 | Joe Riggs | Submission (kimura) |  | UFC 56 | Nov 19, 2005 | 1 | 3:26 | Las Vegas, Nevada, United States |
| Sieg | 38-4 | Frank Trigg | Submission (rear-naked choke) |  | UFC 52 | Apr 16, 2005 | 1 | 4:05 | Las Vegas, Nevada, United States |
| Sieg | 37-4 | Georges St. Pierre | Submission (armbar) |  | UFC 50 | Oct 22, 2004 | 1 | 4:59 | Atlantic City, United States |
| Sieg | 36-4 | Renato Verissimo | Decision (unanimous) |  | UFC 48 | Jun 19, 2004 | 3 | 5:00 | Las Vegas, Nevada, United States |
| Niederlage | 35-4 | B.J. Penn | Submission (rear-naked choke) |  | UFC 46 | Jan 31, 2004 | 1 | 4:39 | Las Vegas, Nevada, US |
| Sieg | 35-3 | Frank Trigg | Submission (standing rear-naked choke) | | UFC 45 | Nov 21, 2003 | 1 | 3:54 | Uncasville, Connecticut, United States |
| Sieg | 34-3 | Sean Sherk | Decision (unanimous) | | UFC 42 | Apr 25, 2003 | 5 | 5:00 | Miami, Florida, United States |
| Sieg | 33-3 | Gil Castillo | TKO (doctor stoppage) | | UFC 40 | Nov 22, 2002 | 1 | 5:00 | Las Vegas, Nevada, United States |
| Sieg | 32-3 | Carlos Newton | TKO (punches) | | UFC 38 | Jul 13, 2002 | 4 | 3:27 | London, England |
| Sieg | 31-3 | Hayato Sakurai | TKO (punches) | | UFC 36 | Mar 22, 2002 | 4 | 3:01 | Las Vegas, Nevada, United States |
| Sieg | 30-3 | Carlos Newton | KO (slam) | | UFC 34 | Nov 02, 2001 | 2 | 1:27 | Las Vegas, Nevada, United States |
| Sieg | 29-3 | Steve Gomm | TKO (punches) | | Extreme Challenge 43 | Sep 08, 2001 | 2 | 3:18 | Orem, Utah, United States |
| Sieg | 28-3 | Hiromitsu Kanehara | Decision (majority) | | Rings: 10th Anniversary | Aug 11, 2001 | 3 | 5:00 | Tokyo, Japan |
| Sieg | 27-3 | Chatt Lavender | Submission (arm triangle choke) | | Extreme Challenge 41 | Jul 13, 2001 | 3 | 2:31 | Davenport, Iowa, United States |
| Sieg | 26-3 | Scott Johnson | KO (punch) | | Extreme Challenge 40 | Jun 16, 2001 | 1 | 3:24 | Springfield, Illinois, United States |
| Sieg | 25-3 | John Cronk | Submission (punches) | | Gladiators 14 | May 11, 2001 | 1 | N/A | Omaha, Nebraska, United States |
| Sieg | 24-3 | Bruce Nelson | Submission (punches) | | Freestyle Combat Challenge 4 | Mar 31, 2001 | 1 | 3:01 | Racine, Wisconsin, United States |
| Sieg | 23-3 | Brett Al-azzawi | Submission (armbar) | | Rings USA: Battle of Champions | Mar 17, 2001 | 1 | 3:27 | Council Bluffs, Iowa, United States |
| Niederlage | 22-3 | José Landi-Jons | KO (F5) | | Shidokan Jitsu: Warriors War 1 | Feb 08, 2001 | 1 | 4:45 | Kuwait City, Kuwait |
| Niederlage | 22-2 | Dennis Hallman | Submission (armbar) | | UFC 29 | Dec 16, 2000 | 1 | 0:20 | Tokyo, Japan |
| Sieg | 22-1 | Maynard Marcum | Submission (keylock) | | Rings Australia: Free Fight Battle | Nov 12, 2000 | 1 | 6:29 | Brisbane, Australia |
| Sieg | 21-1 | Robbie Newman | Submission (arm triangle choke) | | Rings USA: Rising Stars Final | Sep 30, 2000 | 1 | 1:40 | Moline, Illinois, United States |
| Sieg | 20-1 | Chris Haseman | Decision (unanimous) | | Rings: Millennium Combine 3 | Aug 23, 2000 | 2 | 5:00 | Osaka, Japan |
| Sieg | 19-1 | Joe Guist | Submission (armbar) | | Extreme Challenge 35 | Jun 29, 2000 | 1 | 2:45 | Davenport, Iowa, United States |
| Sieg | 18-1 | Marcelo Aguiar | TKO (Doctor Stoppage) | | UFC 26 | Jun 09, 2000 | 1 | 4:34 | Cedar Rapids, Iowa, United States |
| Sieg | 17-1 | Shawn Peters | Submission (arm triangle choke) | | Extreme Challenge 32 | May 21, 2000 | 1 | 2:52 | Springfield, Illinois, United States |
| Sieg | 16-1 | Alexandre Barros | Decision (unanimous) | | WEF 9: World Class | May 13, 2000 | 3 | 5:00 | Evansville, Indiana, United States |
| Sieg | 15-1 | Eric Davila | Submission (keylock) | | SuperBrawl 17 | Apr 15, 2000 | 2 | 3:24 | Honolulu, Hawaii, United States |
| Sieg | 14-1 | Jorge Pereira | TKO (doctor stoppage) | | WEF 8: Goin' Platinum | Jan 15, 2000 | 1 | 6:00 | Rome, Georgia, United States |
| Sieg | 13-1 | Daniel Vianna | KO (slam) | | JKD Challenge 3 | Nov 20, 1999 | 1 | 2:16 | Chicago, Illinois, United States |
| Sieg | 12-1 | LaVerne Clark | Submission (rear-naked choke) | | Extreme Challenge 29 | Nov 13, 1999 | 2 | 1:35 | Hayward, Wisconsin, United States |
| Sieg | 11-1 | Tom Schmitz | Submission (injury) | | Extreme Challenge 29 | Nov 13, 1999 | 1 | 0:48 | Hayward, Wisconsin, United States |
| Sieg | 10-1 | Joe Doerksen | Submission (punches) | | Extreme Challenge 29 | Nov 13, 1999 | 2 | 0:25 | Hayward, Wisconsin, United States |
| Sieg | 9-1 | Valeri Ignatov | Decision (unanimous) | | UFC 22 | Sep 24, 1999 | 3 | 5:00 | Lake Charles, Louisiana, United States |
| Sieg | 8-1 | Akihiro Gono  | Decision (unanimous) | | Shooto - 10th Anniversary Event | May 29, 1999 | 3 | 5:00 | Yokohama, Japan |
| Sieg | 7-1 | Erick Snyder | TKO (slam) | | Jeet Kune Do Challenge 4 | Apr 24, 1999 | 1 | N/A | Chicago, Illinois, United States |
| Sieg | 6-1 | Joe Stern | Submission (punches) | | Extreme Challenge 23 | Apr 02, 1999 | 1 | 2:30 | Indianapolis, Indiana, United States |
| Sieg | 5-1 | Ryan Stout | TKO (corner stoppage) | | Extreme Shootfighting | Dec 11, 1998 | 2 | 5:00 | Waukesha, Wisconsin, United States |
| Niederlage | 4-1 | Dennis Hallman | Technical Submission (standing guillotine choke) | | Extreme Challenge 21 | Oct 17, 1998 | 1 | 0:17 | Hayward, Wisconsin, United States |
| Sieg | 4-0 | Dave Menne | Decision (unanimous) | | Extreme Challenge 21 | Oct 17, 1998 | 1 | 15:00 | Hayward, Wisconsin, United States |
| Sieg | 3-0 | Victor Hunsaker | TKO (punches) | | Extreme Challenge 21 | Oct 17, 1998 | 1 | 1:39 | Hayward, Wisconsin, United States |
| Sieg | 2-0 | Craig Quick | Submission (punches) | | Jeet Kune Do Challenge 2 | Apr 25, 1998 | 1 | N/A | Chicago, Illinois, United States |
| Sieg | 1-0 | Erick Snyder | Submission (slam) | | Jeet Kune Do Challenge 1 | Jan 01, 1998 | 1 | 0:15 | Chicago, Illinois, United States |
