MMA fighter Allan Nascimento died at the age of 34, the UFC announced Monday.

“This morning, Monday, August 3rd, our beloved fighter and exemplary flyweight, Allan Nascimento, was found unresponsive after suffering an apparent heart attack in his sleep,” the promotion wrote in a statement.

“Despite the efforts of the responding medical team, he was pronounced deceased at the scene. Our thoughts and deepest condolences are with Allan’s family, friends, teammates, and loved ones during this incredibly difficult time.”

Allan Nascimento of Brazil prepares to face Mitch Raposo in a flyweight fight during the UFC Fight Night event at Meta APEX on June 20, 2026. Zuffa LLC

Nascimento last fought at the UFC Fight Night: Kape vs. Horiguchi event in June, falling to Mitch Raposo via split decision.

The Brazilian fighter rose to prominence on “Dana White’s Contender Series,” a show in which the UFC president scouts potential talent, losing in a split decision to Raulian Paiva in 2018.

Nascimento found his way onto UFC cards anyway, compiling a 4-2 record, twice earning Fight of the Night performance bonuses.

As a professional, the 5-foot-8, 125-pounder was nicknamed “Puro Osso” — a Portuguese idiom meaning “skin and bones — and put together a 22-7 record.

Allan Nascimento of Brazil elbows Jafel Filho of Brazil in a flyweight fight during the UFC Fight Night event at UFC APEX on May 31, 2025. Zuffa LLC

He trained at Chute Boxe in São Paulo alongside the likes of Charles Oliveira, one of many fighters to offer tributes to the late jiu-jitsu black belt.

“Today I lost a brother that the fight game gave me,” Oliveira wrote in a series of Instagram Stories translated from Portuguese. “Thank you for always being by my side, for sharing the mats and the corner. I have nothing but gratitude for having you with me — in training, in the corner, and just hanging out. I love you, man; you’re a legend.

“My brother, I can’t even believe it; you will be deeply missed.”