Jason Day has 12 losses against 12 opponents on his MMA record. For a list of Day's best fights, refer to "Best fights of Jason Day".
On June 17, 2011 Jason Day faced off against Francis Carmont in a light-heavyweight bout at age 32. He was coming in with a record of 19-12 (17), and Carmont was 29 years old and with a record of 15-7 (13). Day lost the fight via 1st-round TKO.
On July 24, 2010 Jason Day faced off against Ovince St. Preux in a light-heavyweight bout at age 31. He was coming in with a record of 19-11 (17). Day lost the fight via 1st-round KO.
On February 5, 2010 Jason Day faced off against Jesse Taylor in a middleweight bout at age 30. He was coming in with a record of 19-10 (17), and Taylor was 27 years old and with a record of 13-5 (10). Day lost the fight via 1st-round submission.
On March 7, 2009 Jason Day faced off against Kendall Grove in a middleweight bout at age 29. He was coming in with a record of 18-9 (16), and Grove was 26 years old and with a record of 9-5 (7). Day lost the fight via 1st-round TKO.
On June 7, 2008 Jason Day faced off against Michael Bisping in a middleweight bout at age 29. He was coming in with a record of 18-8 (16), and Bisping was 29 years old and with a record of 15-1 (14). Day lost the fight via 1st-round TKO.
On June 1, 2007 Jason Day faced off against Patrick Côté in a middleweight bout at age 28. He was coming in with a record of 13-7 (12), and Côté was 27 years old and with a record of 9-4 (6). Day lost the fight via 1st-round TKO.
On September 8, 2006 Jason Day faced off against Victor Valimaki in a middleweight bout at age 27. He was coming in with a record of 8-6 (7). Day lost the fight via 1st-round submission.
On April 9, 2005 Jason Day faced off against Krzysztof Soszynski at age 26. He was coming in with a record of 3-5 (2), and Soszynski was 27 years old and with a record of 10-2 (10). Day lost the fight via 1st-round TKO.
On May 14, 2004 Jason Day faced off against Ulysses Castro at age 25. He was coming in with a record of 3-4 (2). Day lost the fight via 1st-round KO.
On March 20, 2004 Jason Day faced off against Cameron Brown at age 25. He was coming in with a record of 3-3 (2). Day lost the fight via 1st-round submission.
On October 12, 2003 Jason Day faced off against Derek Tisdale at age 24. He was coming in with a record of 2-2 (2). Day lost the fight via 1st-round submission.
On May 10, 2003 Jason Day faced off against Rodrigo Munduruca at age 24. He was coming in with a record of 2-1 (2). Day lost the fight via 1st-round submission.