UFC Middleweight Champion
Whittaker fought for the interim middleweight title against
Yoel Romero on 8 July 2017 at
UFC 213, after
Michael Bisping announced a nagging knee injury which would go on to keep him on the sidelines for several months.
[59] Whittaker won by unanimous decision, and became the first Australian and first New Zealand born fighter to hold a
UFC title.
[12][60] This win earned him the
Fight of the Night bonus award.
[61] He missed the remainder of 2017, as he was recovering from a
medial knee injury to his left leg.
[62]
On 7 December 2017, then middleweight champion
Georges St-Pierre vacated the
title after being diagnosed with
colitis.
[63] As a result, Whittaker was promoted to undisputed champion.
[64] He was slated for his first title defence at
UFC 221 against former middleweight champion
Luke Rockhold on 10 February 2018 at
Perth Arena in Australia.
[65][66] On 13 January 2018, it was reported that Whittaker had pulled out of the event due to an undisclosed injury and would be replaced by
Yoel Romero for the interim middleweight championship. The winner of this bout would then face Whittaker in a unification bout.
[67] On 20 January 2018, Dana White confirmed that Whittaker was in a serious condition after he was not properly treated from a
staph infection in his stomach.
[68]
A rematch with Romero took place on 9 June 2018 at
UFC 225.
[69] At the weigh-ins, Romero missed weight, coming in at 186 lbs, 1 pound over the middleweight limit for a title fight. Romero was given additional time to make weight, but he weighed in at 185.2 lbs, 0.2 lbs over the title fight limit. Romero was fined 20% of his fight purse and the fight was contested as a non-title catchweight bout.
[70][71] Whittaker won the fight by a close split decision. Their fight was awarded with 'Fight of The Night' honours. As Romero had failed to make weight, Whittaker received a $100,000 bonus, which would normally have been shared by both fighters.
[72]
In July 2018, the UFC announced that Whittaker and
Kelvin Gastelum had been selected as coaches for Ultimate Fighter 28.
[73] On 2 November 2018, it was announced that Whittaker's next middleweight title defence would be against
Kelvin Gastelum, in February at
UFC 234.
[74] However, Whittaker pulled out of the event a few hours beforehand after he was forced to undergo emergency dual surgery immediately, due to an
abdominal hernia of the intestine and a twisted and collapsed bowel.
[75]
Whittaker faced interim middleweight champion
Israel Adesanya on 6 October 2019 at
UFC 243.
[76] He lost the bout and the championship via second-round knockout.
[77]