Guilherme Viana has four losses against four opponents on his MMA record. For a list of Viana's best fights, refer to "Best fights of Guilherme Viana".
On August 21, 2025 Guilherme Viana faced off against Rasul Magomedov in a light-heavyweight bout at age 39. He was coming in with a record of 9-4 (9). Viana lost the fight via 3-round unanimous decision.
On July 22, 2016 Guilherme Viana faced off against Philipe Lins in a light-heavyweight bout at age 30. He was coming in with a record of 7-3 (7). Viana lost the fight via 2nd-round TKO.
On March 27, 2015 Guilherme Viana faced off against Francis Carmont in a light-heavyweight bout at age 28. He was coming in with a record of 6-2 (6), and Carmont was 33 years old and with a record of 22-10 (16). Viana lost the fight via 3-round unanimous decision.
On December 7, 2012 Guilherme Viana faced off against Rodney Wallace in a light-heavyweight bout at age 26. He was coming in with a record of 3-1 (3), and Wallace was 31 years old and with a record of 14-6 (5). Viana lost the fight via 3-round split decision.
