Former UFC and PRIDE Fighting Championships heavyweight champion Antonio Rodrigo Nogueira has officially announced his retirement from the sport of mixed martial arts.

Nogueira made the announcement at a UFC press conference held in Brazil on Tuesday.

The Brazilian has been contemplating retirement ever since his last fight against Stefan Struve at UFC 190 in August in Brazil. Nogueira lost the bout by unanimous decision, which moved his record to 1-4 over his last five fights.

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UFC president Dana White remarked after the card was over that he planned to have a conversation with Nogueira about retirement while also offering him a permanent position with the promotion as a brand ambassador for fighters and fans.

Nogueira accepted the position on Tuesday as he brings his legendary fight career to an end and will begin work with the UFC immediately.

Throughout the past 16 years, Nogueira has been a stalwart in the heavyweight division, well known as one of the most ferocious submission fighters to ever compete in the sport.

He became PRIDE heavyweight champion in 2001 after defeating Heath Herring and would win his next five fights in a row before being dethroned by Fedor Emelianenko.

Nogueira fought against all manner of fighter in his day, including kickboxing legend Semmy Schilt, as well as former pro football player Bob Sapp in a notoriously crazy fight where the Brazilian was driven to the mat directly on his head by his massive opponent before pulling off a second-round armbar submission.

Nogueira also holds wins over several other notable names, including Mirko Cro Cop, Dan Henderson, Josh Barnett and Fabricio Werdum.

He eventually landed in the UFC in 2007 before beating Tim Sylvia to win the heavyweight title in 2008. Nogueira's reign only lasted until his next fight when he was defeated by Frank Mir, and that would mark the end of his time as a champion in MMA.

But Nogueira's influence was still huge as he continued to fight a who's who list of competitors over the years while earning wins over names like Randy Couture and Brendan Schaub along the way.

Nogueira retires with a 34-10-1, 1NC record overall and a legacy as one of the greatest heavyweight mixed martial artists of all time.