UFC 138: Leben vs. Muñoz was a mixed martial arts event held by the Ultimate Fighting Championship on November 5, 2011 at LG Arena in Birmingham, United Kingdom.

[2] The event aired on the same day, via tape delay, on Spike TV in the United States and live on Sportsnet in Canada.

[10] However, on August 30 Krauss pulled out of the bout citing a shoulder injury, and was replaced by Matt Brown.

However, Taylor sustained a whiplash injury during a minor traffic collision on November 1 forcing him from the bout.

[15] After the event Chris Leben tested positive for illegal substances and was subsequently suspended for a year.