| 2012-10-05 | UFC on FX: Browne vs. Bigfoot | Welterweight | Mike Pierce def. Aaron Simpson | KO (punches) | 2 | 0:29 |
| 2012-07-11 | UFC on Fuel TV: Muñoz vs. Weidman | Welterweight | Aaron Simpson def. Kenny Robertson | Decision (unanimous) (30–27, 29–28, 29–28) | 3 | 5:00 |
| 2012-02-15 | UFC on Fuel TV: Sanchez vs. Ellenberger | Middleweight | Ronny Markes def. Aaron Simpson | Decision (split) (29–28, 28–29, 29–28) | 3 | 5:00 |
| 2011-10-08 | UFC 136: Edgar vs. Maynard III | Middleweight | Aaron Simpson def. Eric Schafer | Decision (unanimous) (30–27, 30–27, 30–27) | 3 | 5:00 |
| 2011-07-02 | UFC 132: Cruz vs. Faber | Middleweight | Aaron Simpson def. Brad Tavares | Decision (unanimous) (30–27, 30–27, 30–27) | 3 | 5:00 |
| 2011-03-26 | UFC Fight Night: Nogueira vs. Davis | Middleweight | Aaron Simpson def. Mario Miranda | Decision (unanimous) (30–27, 30–27, 30–26) | 3 | 5:00 |
| 2010-11-20 | UFC 123: Rampage vs. Machida | Middleweight | Mark Muñoz def. Aaron Simpson | Decision (unanimous) (29–28, 29–28, 29–28) | 3 | 5:00 |
| 2010-06-19 | The Ultimate Fighter: Team Liddell vs. Team Ortiz Finale | Middleweight | Chris Leben def. Aaron Simpson | TKO (punches) | 2 | 4:17 |
| 2010-01-11 | UFC Fight Night: Maynard vs. Diaz | Middleweight | Aaron Simpson def. Tom Lawlor | Decision (split) (28–29, 29–28, 29–28) | 3 | 5:00 |
| 2009-08-29 | UFC 102: Couture vs. Nogueira | Middleweight | Aaron Simpson def. Ed Herman | TKO (knee injury) | 2 | 0:17 |
| 2009-04-01 | UFC Fight Night: Condit vs. Kampmann | Middleweight | Aaron Simpson def. Tim McKenzie | TKO (punches) | 1 | 1:40 |