| Fighter | Record | Last Bout |
|---|---|---|
| Marcus Silveira | 6-4-0 (1 NC) | 1997-12-21 |
| 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 |
| Martin Sano | 4-3-1 | 2021-09-25 |
| Martin Svensson | 15-6-0 | 2016-02-27 |
| Matt Sayles | 8-4-0 | 2021-12-18 |
| Matt Serra | 11-7-0 | 2010-09-25 |
| Maurice Smith | 12-14-0 | 2000-11-17 |
| Mike Santiago | 19-12-0 | 2018-06-09 |
| Mike Stumpf | 11-4-0 | 2013-01-26 |
| Mike Swick | 15-6-0 | 2015-07-11 |
| Nate Schroeder | 11-10-0 | 2000-06-09 |
| Neil Seery | 16-13-0 | 2017-07-16 |
| Nick Sanzo | 1-1-0 | 1997-02-07 |
| Nick Serra | 7-3-0 | 2002-06-22 |
| Niklas Stolze | 12-6-0 | 2022-06-04 |
| Pat Schilling | 5-2-0 | 2012-06-01 |
| Patrick Smith | 20-17-0 | 1995-07-14 |
| Paul Sass | 14-2-0 | 2013-02-16 |
| Paulo Santos | 0-3-0 | 1998-10-16 |
| Pete Sell | 10-7-0 | 2009-03-07 |
| Pete Spratt | 25-23-0 | 2007-06-12 |
| Peter Sobotta | 17-7-1 | 2020-07-25 |
| Rameau Thierry Sokoudjou | 18-18-0 | 2008-10-18 |
| Renato Sobral | 37-11-0 | 2007-08-25 |
| Richie Smullen | 3-1-1 | 2018-07-06 |
| Rick Story | 19-9-0 | 2016-08-20 |
| Robert Sanchez | 8-2-0 | 2018-09-08 |
| Roldan Sangcha'an | 4-2-0 | 2015-05-16 |
| Roman Salazar | 10-6-0 (1 NC) | 2015-08-08 |
| Ron Stallings | 14-8-0 (1 NC) | 2015-09-05 |
| Rory Singer | 11-9-0 | 2007-06-16 |
| Rosi Sexton | 13-5-0 | 2013-10-26 |
| Sabah Homasi | 11-8-0 | 2018-01-20 |
| Sabina Mazo | 9-4-0 | 2022-03-12 |
| Saeed Hosseini | 0-1-0 | 1997-05-30 |
| Sage Northcutt | 11-2-0 | 2018-07-14 |
| Sai Wang | 20-6-1 | 2014-08-23 |
| Saidyokub Kakhramonov | 10-3-0 | 2022-12-17 |
| Sako Chivitchian | 8-1-0 | 2010-12-04 |
| Salim Touahri | 10-4-0 | 2019-08-03 |
| Sam Adkins | 7-20-2 | 1996-09-20 |
| Sam Alvey | 33-18-1 (1 NC) | 2022-08-06 |
| Sam Fulton | 0-2-0 | 1997-07-27 |
| Sam Hoger | 10-4-0 | 2007-02-03 |
| Sam Sicilia | 15-8-0 | 2017-02-19 |
| Sam Stout | 20-12-1 | 2015-08-23 |
| Sammy Morgan | 18-12-0 | 2006-08-17 |
| Samy Schiavo | 10-6-0 | 2008-10-18 |