| First | Last | Nickname | Ht. | Wt. | Reach | Stance | W | L | D | Belt |
|---|---|---|---|---|---|---|---|---|---|---|
| Raphael | Uchegbu | 5' 9" | 135 lbs. | 73.0" | Orthodox | 10 | 2 | 0 | ||
| Takeru | Uchida | 5' 5" | 125 lbs. | 68.0" | Southpaw | 6 | 1 | 0 | ||
| Alberto | Uda | 6' 3" | 185 lbs. | -- | Orthodox | 12 | 2 | 0 | ||
| Ryuki | Ueyama | 5' 11" | 180 lbs. | -- | Southpaw | 12 | 18 | 5 | ||
| Christian | Uflacker | 5' 11" | 170 lbs. | -- | 5 | 0 | 0 | |||
| Andy | Uhrich | 6' 0" | 170 lbs. | -- | 11 | 6 | 0 | |||
| Tagir | Ulanbekov | 5' 7" | 125 lbs. | 70.0" | Southpaw | 17 | 2 | 0 | ||
| Carlos | Ulberg | Black Jag | 6' 4" | 205 lbs. | 77.0" | Orthodox | 14 | 1 | 0 | |
| Gasan | Umalatov | Cobra | 5' 11" | 170 lbs. | 71.0" | Orthodox | 17 | 4 | 2 | |
| Jeremy | Umphries | -- | 160 lbs. | -- | 5 | 2 | 0 | |||
| Zach | Underwood | 6' 2" | 185 lbs. | -- | 13 | 7 | 0 | |||
| Caol | Uno | Uno Shoten | 5' 7" | 155 lbs. | 70.0" | Southpaw | 33 | 19 | 5 | |
| Kengo | Ura | Uraken | 5' 9" | 165 lbs. | -- | 14 | 12 | 2 | ||
| Logan | Urban | Hulk | 6' 0" | 170 lbs. | 72.0" | Orthodox | 5 | 1 | 0 | |
| Hector | Urbina | El Toro | 5' 11" | 170 lbs. | 73.0" | Orthodox | 17 | 10 | 1 | |
| Elias | Urbina | 6' 3" | 185 lbs. | 77.0" | Southpaw | 3 | 1 | 0 | ||
| Gilbert | Urbina | The RGV Bad Boy | 6' 3" | 170 lbs. | 75.0" | Orthodox | 7 | 5 | 0 | |
| Guilherme | Uriel | Urso | 6' 1" | 265 lbs. | 74.0" | Orthodox | 6 | 2 | 0 | |
| Nick | Urso | 5' 6" | 125 lbs. | 66.0" | Southpaw | 10 | 3 | 0 | ||
| Yasuhiro | Urushitani | 5' 5" | 125 lbs. | -- | Southpaw | 21 | 8 | 6 | ||
| Sho Patrick | Usami | Savage | 5' 9" | 155 lbs. | 70.0" | Orthodox | 4 | 1 | 0 | |
| Kamaru | Usman | The Nigerian Nightmare | 6' 0" | 170 lbs. | 76.0" | Switch | 21 | 4 | 0 | |
| Mohammed | Usman | The Motor | 6' 2" | 239 lbs. | 79.0" | Orthodox | 12 | 4 | 0 | |
| Darren | Uyenoyama | BC | 5' 6" | 125 lbs. | 65.0" | Orthodox | 10 | 6 | 0 |