Early career Santos made her professional
MMA debut on May 23, 2009, at a
K-1 World Grand Prix event in
Poland. She defeated Magdalena Jarecka by
technical knockout (TKO) in the first round. After winning two of her next three fights, Santos faced undefeated prospect
Cindy Dandois at
M-1 Challenge XXII on December 10, 2010. She defeated Dandois by
TKO in 34 seconds. On November 19, 2011, Santos faced Arune Lauzeckaite at Bushido Hero's World Grand Prix
Lithuania, winning by TKO in the first round. In 2012, Santos faced Ekaterina Saraykina at the Verdict Fighting Championship on February 11, winning by TKO in the first round. In March, she faced Anna Melikhova at Lion's Fights and won by unanimous decision after two rounds. She then defeated Sylwia Kusiak by TKO in round one at the
Baltic Arena in
Koszalin, Poland, in June. Santos was scheduled to face Danielle West at Starlight Events: Gladiator World Cup 2012 on July 6 in
Marbella,
Spain, On August 9, 2012, Santos announced that she was pregnant with her first child. In August 2013, she announced the end of her sports career and her transition to coaching. However, she returned from retirement three years later. She then signed a contract with the
Invicta Fighting Championships.
Invicta Fighting Championships Santos defeated
Tonya Evinger for the Invicta FC Bantamweight title on November 18, 2016. On December 1, the win was overturned to a
no contest, so Evinger retained her title. Santos faced Evinger in a rematch in the main event of
Invicta FC 22 on March 25, 2017, and lost by a
rear-naked choke submission in the second round. Santos defeated
Raquel Pa'aluhi at Invicta FC 25 on August 31, 2017, to win the vacant Invicta FC Bantamweight Championship.
Ultimate Fighting Championship Santos made her UFC promotional debut at
UFC 222 on March 3, 2018, against
Cris Cyborg for the featherweight title. She lost the fight via TKO at 3:25 in the first round. Next, Santos faced
Lina Länsberg on October 6, 2018, at
UFC 229. She won the fight by unanimous decision (30-27). Santos then faced
Marion Reneau on March 9, 2019, at
UFC Fight Night 146. She won the fight by unanimous decision. Santos faced
Aspen Ladd on December 7, 2019, at
UFC on ESPN 7. She lost the fight by technical knockout at 0:33 in round three. Santos was originally scheduled to fight
Ketlen Vieira on August 1, 2020, at UFC Fight Night: Holm vs. Aldana, but the fight was later moved to UFC Fight Night 174 on August 8, 2020. Subsequently, on July 30 Vieira was removed from the card for undisclosed reasons and replaced by
Julija Stoliarenko. Santos won the fight via unanimous decision (30-26, 30-27, 30-27). The bout with
Ketlen Vieira was rescheduled to February 20, 2021, at
UFC Fight Night 185. At the weigh-ins, Vieira weighed 138 pounds (62.6 kg), two pounds over the women's bantamweight non-title fight limit. She was fined 20% of her purse, which went to Santos. The bout proceeded at catchweight. Santos won the fight via unanimous decision (30-27, 30-27, 30-27). Santos faced
Irene Aldana on July 10, 2021, at
UFC 264. At the weigh-ins, Aldana weighed 139.5 pounds (63.28 kg), three and a half pounds over the bantamweight non-title fight limit. Her bout proceeded at catchweight. Aldana was fined 30% of her purse, which went to Santos. Santos lost the fight via technical knockout at 4:35 in round one. Santos faced former
UFC Women's Bantamweight Champion Holly Holm on March 25, 2023, at
UFC on ESPN 43. She lost the fight via unanimous decision (30-26, 30-27). Santos was scheduled to face
The Ultimate Fighter: Heavy Hitters women's featherweight winner
Macy Chiasson on July 1, 2023, at
UFC on ESPN 48 However, Chiasson withdrew two weeks after the fight announcement. She was replaced by
Karol Rosa in a featherweight bout. Santos lost the fight via split decision (28-29, 29-28, 29-28). Santos was scheduled to face
Norma Dumont on January 13, 2024, at
UFC Fight Night 234. However, Santos pulled out due to a broken nose. Santos faced
Chelsea Chandler on August 10, 2024, at
UFC on ESPN 61. At the weigh-ins, Chandler weighed in at 141 pounds (63.96 kg), five pounds over the bantamweight non-title fight limit. The bout proceeded at
catchweight. Chandler was fined 20 percent of her purse, which went to Santos. Santos faced former
UFC Women's Bantamweight Champion Miesha Tate on May 3, 2025, at
UFC on ESPN 67. She won the fight by unanimous decision. Santos faced
Macy Chiasson on October 4, 2025, at
UFC 320. At the weigh-ins, Chiasson weighed in at 137.5 pounds, one and a half pounds over the women's bantamweight non-title fight limit. The bout proceeded at catchweight and Chiasson was fined a percentage of her purse, which went to Santos. Santos won the fight by unanimous decision. Santos was scheduled to face
Norma Dumont on April 25, 2026 at
UFC Fight Night 274. However, for undisclosed reasons, Santos withdrew and was replaced by
Joselyne Edwards. ==Personal life==