Template:Infobox MMA event UFC 36: Worlds Collide was a mixed martial arts event held by the Ultimate Fighting Championship at the MGM Grand Arena on the Las Vegas Strip in Paradise, Nevada on March 22, 2002. The event was seen live on pay per view in the United States, and later released on home video.
The card was headlined by two Title Bouts, a Heavyweight Championship bout between Randy Couture and Josh Barnett and a Welterweight Title Bout between Matt Hughes and Hayato Sakurai. UFC 36 marked the last UFC appearance of former 170 lb Champion Pat Miletich, and the last appearance of Pete Williams. Miletich decided to concentrate on training his fighters, including Matt Hughes who was now the UFC champion in Pat's preferred weight class.
Hughes was originally supposed to fight (at the time) Shooto welterweight champion, and future UFC middleweight champion Anderson Silva. However, Silva had signed a contract with PRIDE Fighting Championships.
Barnett defeated Couture via TKO (strikes) at 4:32 of the second round to become the new UFC Heavyweight Champion. Afterwards, Barnett was stripped of the title when he tested positive for steroids during a mandatory post-fight drug test.
Nine past or future UFC champions competed on this card (including at least one in each bout), more than any other event in UFC history.
- Sherk defeated Nakao via unanimous decision (30–27, 30–27, 30–27).
- Serra defeated Dullanty via submission (triangle choke) at 2:58 of round 1.
- Mir defeated Williams via submission (Mir lock) at 0:46 of round 1.
- Tanner defeated Sinosic via TKO (cut) at 2:06 of round 1.
- Lindland defeated Miletich via TKO (punches) at 3:03 of round 1.
- Rizzo defeated Arlovski via KO (punches) at 1:45 of round 3.
- Hughes defeated Sakurai via TKO (punches) at 3:01 of round 4 to retain the UFC Welterweight Championship.
- Barnett defeated Couture via TKO (punches) at 4:32 of the second round to become the new UFC Heavyweight Champion. Afterwards Barnett would be stripped of the title when he tested positive for steroids during a mandatory post-fight drug test.