| Fighter | Record | Last Bout |
|---|---|---|
| Noad Lahat | 11-2-0 | 2016-02-06 |
| Noe Hernandez | 5-5-0 | 1998-05-15 |
| Nohelin Hernandez | 9-4-0 | 2019-09-28 |
| Nolan Ticman | 4-3-0 | 2015-05-16 |
| Nordine Taleb | 15-7-0 | 2019-09-07 |
| Norifumi Yamamoto | 18-6-0 (2 NC) | 2015-02-28 |
| Norman Parke | 23-6-1 | 2016-02-27 |
| Oleg Taktarov | 17-5-2 | 1995-12-16 |
| Oli Thompson | 17-10-0 | 2012-08-04 |
| Oliver Enkamp | 7-2-0 | 2018-03-17 |
| Olivier Aubin-Mercier | 11-5-0 | 2019-07-27 |
| Oluwale Bamgbose | 6-4-0 | 2017-12-16 |
| Omar Morales | 11-4-0 | 2023-03-18 |
| Omari Akhmedov | 21-6-1 | 2021-07-10 |
| Onassis Parungao | 2-1-0 | 1995-09-08 |
| Orion Cosce | 8-2-0 | 2023-05-20 |
| Orlando Wiet | 1-5-0 | 1994-03-11 |
| Oskar Piechota | 11-3-1 (1 NC) | 2020-06-20 |
| Pablo Garza | 12-4-0 | 2013-04-06 |
| Paddy Holohan | 12-2-1 | 2015-10-24 |
| Paige VanZant | 8-5-0 | 2020-07-11 |
| Pannie Kianzad | 17-9-0 | 2024-08-10 |
| Papy Abedi | 10-4-0 | 2013-08-28 |
| Parker Porter | 14-9-0 | 2023-08-26 |
| Pascal Krauss | 11-2-0 | 2013-08-31 |
| Pat Audinwood | 11-2-1 | 2010-12-11 |
| Pat Barry | 8-7-0 | 2013-12-06 |
| Pat Healy | 34-23-0 (1 NC) | 2014-07-16 |
| Pat Miletich | 29-7-2 | 2002-03-22 |
| Pat Schilling | 5-2-0 | 2012-06-01 |
| Patrick Cote | 23-11-0 | 2017-04-08 |
| Patrick Cummins | 10-7-0 | 2019-05-18 |
| Patrick Smith | 20-17-0 | 1995-07-14 |
| Patrick Walsh | 10-3-0 | 2015-02-14 |
| Patrick Williams | 8-6-0 | 2018-04-14 |
| Paul Bradley | 23-8-0 (2 NC) | 2011-11-12 |
| Paul Buentello | 35-17-0 | 2010-03-21 |
| Paul Creighton | 3-1-0 | 2002-05-10 |
| Paul Daley | 39-15-2 | 2010-05-08 |
| Paul Felder | 17-6-0 | 2020-11-14 |
| Paul Georgieff | 6-2-0 | 2007-12-08 |
| Paul Herrera | 1-1-0 | 1996-02-16 |
| Paul Jones | 11-1-1 | 1999-09-24 |
| Paul Kelly | 14-5-0 | 2011-02-05 |
| Paul Redmond | 12-7-0 | 2015-07-18 |
| Paul Rodriguez | 10-9-2 | 2001-06-29 |
| Paul Sass | 14-2-0 | 2013-02-16 |
| Paul Taylor | 11-6-1 (1 NC) | 2011-02-05 |
| Paul Varelans | 9-9-0 | 1996-12-07 |
| Paulo Santos | 0-3-0 | 1998-10-16 |