UFC 90: Silva vs. Côté was a mixed martial arts event held by the Ultimate Fighting Championship (UFC) on October 25, 2008 at the Allstate Arena in Rosemont, Illinois. The main event featured UFC Middleweight Champion Anderson Silva vs Patrick Côté.

The scheduled bout between Thales Leites and Goran Reljic was scratched from the card due to an injury suffered by Reljic. Drew McFedries was chosen as Reljic's replacement. Anderson Silva's original opponent was rumored to be Yushin Okami, but the fight was scratched after Okami suffered a hand injury. Also, the bout between Gray Maynard and Rich Clementi was moved to the main card.

Diego Sanchez suffered an injury while preparing for his bout against Thiago Alves and was forced to pull out while Josh Koscheck stepped in to fight instead.

Other changes to the card included:

Future UFC Heavyweight Champion Junior dos Santos made his UFC debut at this event.

All fighters were awarded an extra $65,000.

Anderson da Silva (Portuguese pronunciation: [ˈɐ̃deʁsõ ˈsiwvɐ]; born April 14, 1975) is a Brazilian mixed martial artist. He is the current UFC Middleweight Champion and the promotion's longest reigning champion. With 14 consecutive wins and 9 title defenses, Silva holds the longest winning streak and title defense streak in UFC history.

Silva is ranked as the number one Middleweight in the world by multiple publications, and is the consensus No. 1 pound-for-pound fighter in the world according to ESPN, Sherdog, Yahoo! Sports, MMAFighting.com and other publications. UFC president Dana White has proclaimed Silva as "the greatest mixed martial artist ever."^{[undue weight? – discuss]} Silva is also the last Cage Rage Middleweight Champion and a former Shooto Middleweight Champion. Besides the UFC and Cage Rage, Silva has fought for a number of other MMA promotions including the Pride Fighting Championships, Shooto and Rumble on the Rock.

Although known primarily for his mastery of Muay Thai striking, Silva is also a Brazilian Jiu-Jitsu blackbelt, a rank he earned in 2006 from Antônio Rodrigo Nogueira who follows Gracie Lineage through Carlson Gracie, like Murilo Bustamante and the Brazilian Top Team. He began martial arts training at the age of 14, training Tae kwon do and earning a black belt by the age of 18. He is also a black belt in Judo and a yellow rope in Capoeira.

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.

Fabricio Werdum (Portuguese pronunciation: [faˈbɾisju veʁˈdũ]; born July 30, 1977) is a Brazilian mixed martial artist, a two-time Brazilian Jiu-Jitsu world champion, a two-time ADCC world heavyweight champion and European Jiu-Jitsu champion. He holds black belts in Brazilian Jiu-Jitsu,Judo, and Muay Thai. Werdum has competed in Pride Fighting Championships, the Ultimate Fighting Championship, and made his Strikeforce debut on August 15, 2009. He is currently ranked the #4 heavyweight in the world by Sherdog and the #6 heavyweight fighter in the world by MMAWeekly. He was the first fighter to decisively defeat Fedor Emelianenko in mixed martial arts competition.

Born in Porto Alegre, Brazil, Werdum started training Brazilian Jiu-Jitsu after a recommendation from his ex-girlfriend. He trained with Marcio Corleta at the Porto Alegre Academy, Winner Behring. After success in competitive BJJ and submission wrestling, he started his career in MMA.

He arrived in Spain to join his mother, who had moved to the city of Madrid some years before. At the age of 17, soon after his arrival in Spain, when he was just a purple belt, he started teaching the art of BJJ in Madrid and other cities of Spain. Despite only training with white and blue belts, he became BJJ World Champion, being promoted to the rank of black belt by Master Sylvio Behring 3 years later.

Thiago Alves d'Araujo (Portuguese pronunciation: [tʃiˈaɡu ˈawvis]; born October 3, 1983) is a Brazilian mixed martial artist currently competing as a welterweight in the Ultimate Fighting Championship. He started training in Muay Thai when he was 15 and mixed martial arts at 17. He is a brown belt in Brazilian Jiu-Jitsu and has been described as a "Muay Thai wrecking machine".

After beginning his fight training at the age of 14, Alves won his first professional bout at just 15 years old, defeating a 25-year-old by unanimous decision. At 19, Thiago relocated from Brazil to Coconut Creek, Florida to train full-time at the prestigious American Top Team camp.

After beginning his career in smaller organizations such as the Ironheart Crown, Absolute Fighting Championships and King of the Cage, Alves, with a record of 8–3, received an invitation to make his UFC debut at Ultimate Fight Night 2 against fellow UFC newcomer Spencer Fisher, The fight would take place on Alves' twenty-second birthday.