Oliveira weighed in at 155.5 pounds, which was a half-pound over the limit for his lightweight fight with Justin Gaethje.
It means that Oliveira’s title will now be vacant and Gaethje could take home the belt should he win the pair’s fight on Sunday.
It was the first time a UFC champion had lost their belt after failing to make weight.
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Oliveira was given an additional hour to cut the weight but missed again on his second attempt, with the UFC confirming in a later statement he had been stripped of his title.
The statement also added that Oliveira will forfeit a percentage of his purse and that should he win on Sunday, he will be the number one contender for the vacant lightweight championship.
The decision did not go down well in some sections of the UFC world, with lightweight fighter Paul Felder teeing off.
“Wonder if he still wants to fight at 145. I have nothing against the champ. But this is a disgrace. And I honestly feel most for Justin. What an absolute let down for everyone in the division,” he wrote on Twitter.
Ariane Carnelossi, who is fighting Lupita Godinez at UFC 274, also hit out amid accusations of tampering with the scales.
“Congrats to the “genius” that messed with the fighter’s scale leaving it with a 0.5lb difference. We only found out when we were informed as we were coming down to check our official Weight. Luckly [sic] I was under so that didnt hurt me,” she wrote.