| Fighter | Record | Last Bout |
|---|---|---|
| Gideon Ray | 17-15-1 | 2006-11-11 |
| Gillian Robertson | 17-9-0 | 2026-08-15 |
| Goran Reljic | 15-8-0 | 2010-11-13 |
| Gregory Rodrigues | 20-6-0 | 2026-08-22 |
| Hector Ramirez | 10-6-1 | 2007-06-16 |
| Imanol Rodriguez | 7-0-0 | 2026-10-03 |
| Irwin Rivera | 10-6-0 | 2020-09-19 |
| Jairzinho Rozenstruik | 15-6-0 | 2025-02-01 |
| Jake Rosholt | 12-5-0 (1 NC) | 2009-11-21 |
| Jared Rollins | 8-4-0 | 2007-12-08 |
| Jared Rosholt | 14-4-0 | 2016-02-06 |
| Jason Reinhardt | 20-3-0 | 2011-08-14 |
| Javier Reyes | 23-6-0 | 2026-06-27 |
| Jerome Rivera | 10-6-0 | 2021-07-10 |
| Jesse Ronson | 21-12-0 (1 NC) | 2022-10-01 |
| Jessica Rakoczy | 1-5-0 (1 NC) | 2015-04-25 |
| Jessie Rosas | 8-1-0 | 2026-09-12 |
| Jimmie Rivera | 23-5-0 | 2021-02-27 |
| Joao Roque | 7-2-4 | 2000-06-09 |
| Joe Riggs | 44-17-0 (1 NC) | 2016-02-21 |
| Joey Roberts | 4-3-0 | 1999-03-05 |
| Johnny Rees | 13-5-0 (1 NC) | 2008-12-10 |
| Johnny Rhodes | 2-1-0 | 1994-03-11 |
| Jon Delos Reyes | 8-5-0 | 2015-10-24 |
| Jordan Radev | 23-5-0 | 2007-12-29 |
| Jordan Rinaldi | 14-7-0 | 2019-03-16 |
| Jorge Rivera | 20-9-0 | 2012-01-20 |
| Josh Rafferty | 9-8-0 | 2005-04-09 |
| Juancamilo Ronderos | 4-2-0 | 2023-02-18 |
| Karl Roberson | 9-6-0 | 2022-07-09 |
| Karol Rosa | 19-8-0 | 2026-06-20 |
| Keith Rockel | 12-4-1 | 2003-11-21 |
| Kenny Robertson | 15-5-0 | 2016-09-17 |
| Kevin Randleman | 17-16-0 | 2002-01-11 |
| Kevin Rosier | 2-6-0 | 1994-12-16 |
| Khalil Rountree Jr. | 15-7-0 (1 NC) | 2025-10-04 |
| Kleydson Rodrigues | 8-4-0 | 2024-05-18 |
| Kristian Rothaermel | 4-3-0 | 2006-06-28 |
| Leigh Remedios | 18-10-2 | 2002-07-13 |
| Levi Rodrigues Jr. | 5-2-0 (1 NC) | 2026-08-29 |
| Loik Radzhabov | 18-6-1 | 2024-07-20 |
| Lucas Rocha | 18-2-0 | 2025-10-11 |
| Luis Ramos | 20-10-2 | 2012-06-22 |
| Luke Riley | 14-0-0 | 2026-07-11 |
| Luke Rockhold | 16-6-0 | 2022-08-20 |
| Manuel Rodriguez | 11-5-0 | 2012-12-14 |
| Mara Romero Borella | 12-9-0 (2 NC) | 2020-09-19 |
| Marcelo Rojo | 16-10-0 | 2022-12-03 |
| Marco Polo Reyes | 8-7-0 | 2019-09-21 |
| Marco Ruas | 9-4-2 | 1999-07-16 |