Ortiz returned at UFC XVIII against Mezger's teamate, Jerry Bohlander. Ortiz beat Bohlander in a bloody fight. Tito then got a rematch against Mezger at UFC XIX. The fight lasted for 9:56, ending when Mezger was too exhausted to defend himself. Ortiz then got a shot at the Middleweight champion, Frank Shamrock. The battle went for 4 rounds with Tito controlling the action and ahead on the judges card. He wore out and ended up on his hands and knees in front of Shamrock and received several elbows and punches to the head, causing the tapout.

Frank Shamrock retired from the UFC, leaving the Middleweight belt vacant. Tito Ortiz was considered an obvious choice for the champion, and faced Vanderlei Silva in a match at UFC XXV to determine the new champ. Tito and Silva beat each other for 5 rounds, but Ortiz came out ahead on the score cards, and was crowned the new UFC Middleweight Champion. Tito's first defense of the belt would be against Japanese sensation Yuki Kondo at UFC XXIX. Kondo came out strong and hit Tito with a flying knee to the face, but Ortiz went into a rage and anhilated Kondo with a flurry of punches and elbows, causing him to tapout @ 1:52.

UFC officials instituted new weight classes and Ortiz's title was changed from Middleweight champion to Light-Heavyweight Champion. Tito was then slated to defend his belt against undefeated Extreme Fighting Champion Evan Tanner at UFC XXX. Many expected this to be one of the greatest fights of the octagon, but Tito ended it in 30 seconds with a bodyslam that KO'ed Tanner. Tito then faced Elvis Sinosic at UFC XXXII: Showdown in the Meadowlands. Sinosic surprised the world with a quick and easy victory over Jeremy Horn, who is considered one of the best fighters in the world. Tito felt Sinosic out for a few moments, but caught with a solid punch, so he took Sinosic down and dispatched him rather easily with forearms and punches. The fight was stopped due to a huge cut on Sinosic's forehead. Tito then was supposed to battle Vitor Belfort at UFC 33, but Belfort lacerated his tricep and had to withdraw. Vladimir Matyushenko was the replacement. Many expected to see Tito to be on his back for once, but they were wrong. Tito completely dominated the fight for five rounds, beating Matyushenko to a bloody pulp. Ortiz walked away with a Unanimous Decision.

Other Facts: Tito Ortiz was a two time California state wrestling champion, with a 52-1 record. He competed in the 2000 Abu Dhabi Submission Wrestling World Championships in Saudi Arabia where he defeated fellow UFC vet Matt Hughes and nearly won his division. Tito has also started a charity, The Tito Ortiz Foundation, to help inner-city kids who grow up in the same conditions that Ortiz did. He is also featured in the UFC game for Sega Dreamcast and Sony Playstation. He "shares" the cover with Guy Mezger.