UFC 2009 Undisputed, also known as UFC Undisputed 2009, is a featuring properties and fighters developed by and published by . The game was released for and . It is the first game to be released under THQ's 2007 agreement with the UFC, and it is to be the first UFC game released since in 2004. A playable demo of UFC 2009 was released onto Xbox Live and PlayStation Network on 23 April 2009, and featured a tutorial and exhibition matchup between and . A sequel, , was released on 25 May 2010.
The game received "favourable" reviews on both platforms according to the website . In Japan, gave it a score of one nine and three eights for a total of 33 out of 40. Some reviews cited the lack of a penalty for users who disconnect from online games as a negative aspect, along with lag in online play. Although recently, there had been a patch that must be downloaded, that is preventing "cheating" with the CAF program, by stopping a bug that players were able to exploit an error in the CAF system, that allowed artificial "pumping up" of the CAF's ability meters. This patch is also supposed to be able to track those players that disconnect in an attempt to falsely prevent losses from showing up on the CAF's Win-Loss record. It is also supposed to try to prevent lag issues, by matching up players with similar connection speeds. 's Daniel Wilks commended the game for its "very deep, intricate fighting system [and] balanced striking and ground game." However, he criticized it for its "very steep learning curve [and] very appeal".
According to NPD figures, UFC 2009: Undisputed managed to sell over 1,000,000 units in its first month. 679,600 of these sales came on the Xbox 360, with 334,400 coming on the PlayStation 3. By February 2010, the game sold 3.5 million copies.
At the , UFC 2009 Undisputed was named the Best Individual Sports Game.