| Fighter | Record | Last Bout |
|---|---|---|
| Mark Holst | 12-6-0 | 2010-10-16 |
| Mark Hominick | 20-12-0 | 2012-11-17 |
| Mark Hughes | 6-2-0 | 2000-11-17 |
| Mark Hunt | 13-14-1 (1 NC) | 2018-12-01 |
| Mark Kerr | 15-11-0 (1 NC) | 1997-10-17 |
| Mark Madsen | 12-2-0 | 2023-11-11 |
| Mark Munoz | 14-6-0 | 2015-05-16 |
| Mark Robinson | 1-0-0 (1 NC) | 2001-02-23 |
| Mark Scanlon | 9-2-0 | 2010-11-13 |
| Mark Schultz | 1-1-0 | 1996-05-17 |
| Mark Striegl | 18-4-0 (1 NC) | 2022-02-19 |
| Mark Vologdin | 12-5-2 | 2026-08-01 |
| Mark Weir | 21-18-1 | 2003-04-25 |
| Markus Perez | 12-5-0 | 2021-01-20 |
| Marlon Moraes | 23-10-1 | 2022-03-12 |
| Marlon Vera | 23-12-1 | 2026-09-19 |
| Marnic Mann | 6-3-0 | 2024-04-27 |
| MarQuel Mederos | 12-1-1 | 2026-08-22 |
| Martin Bravo | 11-3-0 | 2019-09-21 |
| Martin Buday | 16-2-0 | 2025-07-26 |
| Martin Day | 8-6-0 | 2021-02-06 |
| Martin Kampmann | 20-7-0 | 2013-08-28 |
| Martin Sano | 4-3-1 | 2021-09-25 |
| Martin Svensson | 15-6-0 | 2016-02-27 |
| Marvin Eastman | 18-15-1 | 2008-06-21 |
| Marvin Vettori | 19-10-1 | 2026-10-03 |
| Marwan Rahiki | 9-0-0 | 2026-09-12 |
| Maryna Moroz | 11-6-0 | 2024-03-09 |
| Masanori Kanehara | 26-12-5 | 2016-01-02 |
| Masio Fullen | 11-7-0 | 2016-01-30 |
| Mason Jones | 18-3-0 (1 NC) | 2026-08-22 |
| Masutatsu Yano | 2-4-1 | 1999-11-19 |
| Mateus Mendonca | 10-3-0 | 2024-02-24 |
| Mateusz Gamrot | 26-5-0 (1 NC) | 2026-08-08 |
| Mateusz Rebecki | 21-5-0 | 2026-08-01 |
| Matheus Camilo | 11-3-0 | 2026-06-27 |
| Matheus Nicolau | 19-6-1 | 2024-10-19 |
| Mats Nilsson | 11-4-1 | 2015-01-03 |
| Matt Andersen | 14-8-1 | 1996-05-17 |
| Matt Arroyo | 3-3-0 | 2009-01-31 |
| Matt Bessette | 22-9-0 (1 NC) | 2018-07-06 |
| Matt Brown | 26-19-0 | 2023-05-13 |
| Matt Dwyer | 9-4-0 | 2016-01-30 |
| Matt Frevola | 11-6-1 | 2025-10-18 |
| Matt Grice | 15-5-0 | 2013-02-23 |
| Matt Hamill | 12-8-0 | 2013-10-09 |
| Matt Hobar | 9-3-0 | 2014-12-06 |
| Matt Horwich | 30-25-1 | 2009-04-01 |
| Matt Hughes | 45-9-0 | 2011-09-24 |
| Matt Lindland | 22-9-0 | 2005-08-20 |