Aaron Simpson has five losses against five opponents on his MMA record. For a list of Simpson's best fights, refer to "Best fights of Aaron Simpson".
On March 23, 2013 Aaron Simpson faced off against Joshua Burkman in a welterweight bout at age 38. He was coming in with a record of 12-5 (7). Simpson lost the fight via 1st-round KO.
On October 5, 2012 Aaron Simpson faced off against Mike Pierce in a welterweight bout at age 38. He was coming in with a record of 12-4 (7), and Pierce was 32 years old and with a record of 14-5 (7). Simpson lost the fight via 2nd-round KO.
On February 15, 2012 Aaron Simpson faced off against Ronny Markes at age 37. He was coming in with a record of 11-3 (7), and Markes was 23 years old and with a record of 12-1 (9). Simpson lost the fight via 3-round split decision.
On November 20, 2010 Aaron Simpson faced off against Mark Muñoz at age 36. He was coming in with a record of 8-2 (7), and Muñoz was 32 years old and with a record of 8-2 (5). Simpson lost the fight via 3-round unanimous decision.
On June 19, 2010 Aaron Simpson faced off against Chris Leben at age 35. He was coming in with a record of 8-1 (7), and Leben was 29 years old and with a record of 19-7 (14). Simpson lost the fight via 2nd-round TKO.
