Aaron "A-Train" Simpson
| First Name : | Aaron |
| Last name : | Simpson |
| Nickname : | A-Train |
| Height : | 6'0" (183cm) |
| Weight : | 185 lbs (84 kg) |
| City : | Phoenix, Arizona |
| Country : | USA |
| Record : | 4 - 2 - 0 (Wins - Losses - Draws) |
| Wins : |
2 TKO (Punches) (50%) 1 TKO (Knee Injury) (25%) 1 KO (Punch) (25%) |
| Losses : |
1 TKO (Punches) (50%) 1 Decision (Unanimous) (50%) |
| Association : | Arizona Combat Sports |
| Match Stats | ||||||
| Result | Opponent | Method | Event Title | Date | Round | Time |
| Lost | Mark Munoz | Decision (Unanimous) | UFC 123 - Rampage vs. Machida | Nov 20, 2010 | 3 | 5:00 |
| Lost | Chris Leben | TKO (Punches) | TUF 11 Live Finale | Jun 19, 2010 | 2 | 4:17 |
| Win | Ed Herman | TKO (Knee Injury) | UFC 102 - Couture vs. Nogueira | Aug 29, 2009 | 2 | 0:17 Sec |
| Win | Tim McKenzie | TKO (Punches) | UFC - Fight Night 18 | Apr 1, 2009 | 1 | 1:40 Sec |
| Win | David Avellan | KO (Punch) | WEC 36 - Faber vs. Brown | Nov 5, 2008 | 1 | 0:18 Sec |
| Win | Scott Dingman | TKO (Punches) | Tuff-N-Uff - Thompson vs. Troyer | Feb 1, 2008 | 1 | 2:40 Sec |