UFC 131: Dos Santos vs. Carwin was a mixed martial arts event held by the Ultimate Fighting Championship on June 11, 2011 at the Rogers Arena in Vancouver, British Columbia.

Brock Lesnar was originally scheduled to face Junior dos Santos after their coaching stint on The Ultimate Fighter 13, but due to a recurring illness, Lesnar was replaced by Shane Carwin. Originally, a matchup between Carwin , and Jon Olav Einemo was scheduled for this event. Einemo remained on the card and faced Dave Herman, who was pulled from a matchup with Joey Beltran as a result. Beltran was matched up with Aaron Rosa.

Court McGee was scheduled to fight Jesse Bongfeldt, but was forced to pull out due to a torn MCL while training and was replaced by Chris Weidman

Rani Yahya was scheduled face Dustin Poirier at this event, but withdrew due to injury on May 3, 2011 and was replaced by UFC newcomer Jason Young.

Anthony Perosh was expected to face Krzysztof Soszynski at this event, but Perosh was forced from the bout with an injury and replaced by Igor Pokrajac. However, Pokrajac was forced to pull out of the bout due to injuries just days before the event and was replaced by Mike Massenzio. The Soszynski/Pokrajac bout was later rescheduled for UFC 140, where Pokrajac won by knockout.

Brock Edward Lesnar (/ˈlɛznər/; born July 12, 1977) is an American professional wrestler, actor, former mixed martial artist and amateur wrestler, signed with WWE and appearing on its Raw brand. He is also a former UFC Heavyweight Champion and former #1 ranked mixed martial arts (MMA) Heavyweight by Sherdog; he was ranked #5 before he announced his retirement at the end of 2011. Lesnar is an accomplished amateur wrestler, winning the 2000 NCAA heavyweight wrestling championship and placing second in 1999, losing in the finals to 1999 world freestyle wrestling champion and future New England Patriots offensive lineman Stephen Neal.

He gained prominence in World Wrestling Entertainment (WWE) from 2002 to 2004, where he is a former three-time WWE Champion, becoming the youngest WWE Champion at age 25 with his first reign. Lesnar was the 2002 King of the Ring and the winner of the 2003 Royal Rumble. After leaving WWE, Lesnar pursued a career in the NFL. He played during the preseason for the Minnesota Vikings, but ended up being a late cut. Lesnar returned to professional wrestling at the end of 2005, and joined New Japan Pro Wrestling (NJPW), where he won the IWGP Heavyweight Championship in his first match. He was officially stripped of the title by NJPW in July 2006, and took the physical belt with him to Inoki Genome Federation (IGF), where he was still recognized as IWGP Champion until June 2007.

Junior dos Santos Almeida (Brazilian Portuguese pronunciation: [ˈʒũnjoʁ dus ˈsɐ̃tus]), also known as Junior Cigano ("Gipsy"; born September 12, 1984), is a Brazilian professional mixed martial artist and the current UFC Heavyweight Champion. He is ranked as the number one heavyweight fighter in the world by numerous media outlets.

Dos Santos started training Brazilian Jiu-Jitsu under Yuri Carlton for fitness reasons. After some time he was invited to join an MMA practice, where he met his boxing coach Luiz Carlos Dórea, and after roughly a year he made his debut fight.

Dos Santos became professional in 2006 at the age of 21. He fought in small promotions in Brazil, such as Demo Fight, Extreme Fighting Championship, Minotauro Fights and Mo Team League. He won 6 out of his first 7 bouts, suffering his only loss to Joaquim Ferreira, a fighter he'd previously beaten.

Dos Santos debuted for the UFC on October 25, 2008 at UFC 90. Considered a major underdog, dos Santos knocked out top contender Fabricio Werdum at a minute and twenty-one seconds of the first round with a strong uppercut, earning himself a "Knockout of the Night" award.

Dana White (born July 28, 1969) is the current President of the Ultimate Fighting Championship (UFC), a mixed martial arts organization based in the United States.

Born in Manchester, Connecticut on July 28, 1969, White grew up in Las Vegas, Nevada, Ware, Massachusetts and Levant, Maine. White is a passionate Boston Red Sox fan. During his youth, he bounced back and forth between Boston and Maine. He attended the University of Massachusetts Boston but did not finish; however, while there he did launch a boxing program for inner-city youth.

White has a background as an aerobics instructor. In 1992, White established Dana White Enterprises in Las Vegas. He conducted aerobics classes at three gyms in the Las Vegas area and began managing MMA fighters Tito Ortiz and Chuck Liddell.

While working as a manager, White learned that Semaphore Entertainment Group, the parent company of the UFC, was looking for a buyer for the UFC. White contacted childhood friend Lorenzo Fertitta, an executive at Station Casinos, and a former commissioner of the Nevada State Athletic Commission. Within a month, Lorenzo and his older brother Frank bought the UFC, with White installed as its president. White currently owns about 9% of Zuffa, LLC, the entity the Fertitta brothers created to own and manage the UFC.

Kenneth Alan Florian (born May 26, 1976) is a retired Peruvian-American mixed martial artist who formerly competed as a lightweight in the Ultimate Fighting Championship. He has a background in Brazilian Jiu-Jitsu and Muay Thai, and is known for his cerebral approach to the sport based on his meticulous game plans and well-articulated fight analysis. He is also known for his tendency to finish his opponents, having earned stoppages in 12 of his 14 career victories, and for his devastating elbow strikes. He is the only fighter in history to compete in four different weight divisions under the UFC banner, Also Florian is the only fighter currently in the UFC to not have won a title after fighting for the belt three times.

Florian first gained recognition for his appearance on the inaugural season of The Ultimate Fighter reality show. He holds notable victories over former PRIDE champion Takanori Gomi, current UFC contenders Clay Guida, Roger Huerta, Joe Lauzon, Din Thomas, Joe Stevenson, Sam Stout, and Diego Nunes. He has competed for the UFC Lightweight Championship twice and the UFC Featherweight Championship, but came up short against Sean Sherk, BJ Penn, and Jose Aldo. He is currently ranked as the #4 featherweight in the world by MMA Fighting and as the #10 featherweight fighter in the world by MMAWeekly.