Poids Mouches Hommes
 | Joshua Perreira | 1-0-0 REC | #6674 |  |
 | Joshua Van | 10-1-0 UFC | #22 |  |
 | Josiah Reyes | 1-1-0 REC | #5531 | |
 | Jostin Quilca | 0-1-0 REC | #5853 |  |
 | Josua Hernandez | 0-1-0 REC | #7038 |  |
 | Juan Puerta | 1-0-0 REC | #7267 | |
 | Juancamilo Ronderos | 0-2-0 UFC | #5061 |  |
 | Jung Hyun Lee | 1-2-0 REC | #1892 |  |
 | Junior Assis | 0-1-0 REC | #7640 |  |
 | Juscelino Pantoja | 0-1-0 REC | #5965 | |
 | Jussier da Silva | 9-7-0 UFC | #1048 | |
 | Justin Scoggins | 4-5-0 UFC | #2713 | |
 | Kai Kara-France | 8-5-0 UFC | #548 |  |
 | Kai Yoshida | 0-1-0 REC | #5434 |  |
 | Kaito Oda | 0-1-0 REC | #6299 | |
 | Kanean Catron | 1-0-0 REC | #1890 | |
 | Kayck Alencar | 0-1-0 REC | #6308 | |
 | Kelvin Martinez | #8233 | | |
 | Kendrick Latchman | 0-1-0 REC | #6152 | |
 | Kentaro Tomita | 0-1-0 REC | #6782 | |