| 2017-06-25 | UFC Fight Night: Chiesa vs. Lee | Featherweight | Dennis Siver def. B.J. Penn | Decision (majority) (28–28, 29–28, 29–27) | 3 | 5:00 |
| 2015-06-20 | UFC Fight Night: Jędrzejczyk vs. Penne | Featherweight | Tatsuya Kawajiri def. Dennis Siver | Decision (unanimous) (29–28, 29–28, 29–28) | 3 | 5:00 |
| 2015-01-18 | UFC Fight Night: McGregor vs. Siver | Featherweight | Conor McGregor def. Dennis Siver | TKO (punches) | 2 | 1:54 |
| 2014-10-04 | UFC Fight Night: Nelson vs. Story | Featherweight | Dennis Siver def. Charles Rosa | Decision (unanimous) (30–27, 30–27, 30–27) | 3 | 5:00 |
| 2013-12-28 | UFC 168: Weidman vs. Silva 2 | Featherweight | Dennis Siver vs. Manny Gamburyan | No contest (overturned; original: No Contest (overturned)) | 3 | 5:00 |
| 2013-07-06 | UFC 162: Silva vs. Weidman | Featherweight | Cub Swanson def. Dennis Siver | TKO (punches) | 3 | 2:24 |
| 2012-12-08 | UFC on Fox: Henderson vs. Diaz | Featherweight | Dennis Siver def. Nam Phan | Decision (unanimous) (30–24, 30–25, 30–26) | 3 | 5:00 |
| 2012-04-14 | UFC on Fuel TV: Gustafsson vs. Silva | Featherweight | Dennis Siver def. Diego Nunes | Decision (unanimous) (29–28, 29–28, 29–28) | 3 | 5:00 |
| 2011-10-29 | UFC 137: Penn vs. Diaz | Lightweight | Donald Cerrone def. Dennis Siver | Submission (rear-naked choke) | 1 | 2:22 |
| 2011-07-02 | UFC 132: Cruz vs. Faber | Lightweight | Dennis Siver def. Matt Wiman | Decision (unanimous) (29–28, 29–28, 29–28) | 3 | 5:00 |
| 2011-02-27 | UFC 127: Penn vs. Fitch | Lightweight | Dennis Siver def. George Sotiropoulos | Decision (unanimous) (29–28, 30–28, 30–27) | 3 | 5:00 |
| 2010-11-13 | UFC 122: Marquardt vs. Okami | Lightweight | Dennis Siver def. Andre Winner | Submission (rear-naked choke) | 1 | 3:37 |
| 2010-06-19 | The Ultimate Fighter: Team Liddell vs. Team Ortiz Finale | Lightweight | Dennis Siver def. Spencer Fisher | Decision (unanimous) (30–27, 29–28, 29–28) | 3 | 5:00 |
| 2010-03-31 | UFC Fight Night: Florian vs. Gomi | Lightweight | Ross Pearson def. Dennis Siver | Decision (unanimous) (30–27, 30–27, 30–27) | 3 | 5:00 |
| 2009-11-14 | UFC 105: Couture vs. Vera | Lightweight | Dennis Siver def. Paul Kelly | TKO (spinning back kick and punches) | 2 | 2:53 |
| 2009-06-13 | UFC 99: The Comeback | Lightweight | Dennis Siver def. Dale Hartt | Submission (rear-naked choke) | 1 | 3:23 |
| 2009-01-17 | UFC 93: Franklin vs. Henderson | Lightweight | Dennis Siver def. Nate Mohr | TKO (spinning back kick and punches) | 3 | 3:47 |
| 2008-07-05 | UFC 86: Jackson vs. Griffin | Lightweight | Melvin Guillard def. Dennis Siver | TKO (punches) | 1 | 0:36 |
| 2008-01-23 | UFC Fight Night: Swick vs. Burkman | Lightweight | Gray Maynard def. Dennis Siver | Decision (unanimous) (29–28, 30–27, 29–28) | 3 | 5:00 |
| 2007-09-08 | UFC 75: Champion vs. Champion | Lightweight | Dennis Siver def. Naoyuki Kotani | KO (punch) | 2 | 2:04 |
| 2007-04-21 | UFC 70: Nations Collide | Welterweight | Jess Liaudin def. Dennis Siver | Submission (armbar) | 1 | 1:21 |