Michaà  Oleksiejczuk (born February 22, 1995) is a Polish mixed martial artist. A professional since 2014, he was the former Thunderstrike Fight League Light heavyweight champion in Poland. He currently competes in the middleweight division of the Ultimate Fighting Championship (UFC).
Michal played handball before taking up martial arts. Oleksiejczuk has a younger brother named Cezary, who is also a professional mixed martial artist.
Oleksiejczuk started his MMA career in 2014. Fighting primarily in Poland, he amassed a record of 12âÂÂ2 before being signed by UFC in 2017. During this time Oleksiejczuk won the Wenglorz Fight Cup tournament, as well as the thunderstrike fight league light heavyweight championship.
Oleksiejczuk was expected to have made his UFC debut to face Ion CuÃÂelaba on November 4, 2017, at UFC 217, replacing injured Gadzhimurad Antigulov. In turn after the weigh-ins, CuÃÂelaba was pulled from the event by USADA due to a potential Anti-Doping Policy violation stemming from its investigation into voluntary disclosures by CuÃÂelaba during an out-of-competition sample collections on October 18 and October 19. CuÃÂelaba was provisionally suspended and the bout was scrapped.
Oleksiejczuk's UFC debut was finally set on December 30, 2017, facing Khalil Rountree Jr. and replacing injured Gökhan Saki, at UFC 219. However, after the fight, it was revealed that Oleksiejczuk had tested positive for clomiphene, an anti-estrogenic substance. As a result, the Nevada Athletic Commission (NAC) officially overturned the result of the fight to a no contest and Oleksiejczuk received one year suspension by USADA.
Oleksiejczuk returned to octagon one year later to face Gian Villante on February 23, 2019, at . He won the fight via TKO due to a body punch early in the first round. This win earned him the Performance of the Night award.
Oleksiejczuk faced Gadzhimurad Antigulov on April 20, 2019, replacing Roman Dolidze, at . Oleksiejczuk won the fight via knockout in the first round.
Oleksiejczuk faced Ovince Saint Preux on September 28, 2019, at UFC on ESPN+ 18. He lost the fight via submission due to a Von Flue choke in the second round.
Oleksiejczuk faced Jimmy Crute on February 23, 2020, at UFC Fight Night 168. He lost the fight via a kimura submission in the first round.
Oleksiejczuk faced Modestas Bukauskas on March 27, 2021, at UFC 260. He won a close bout via split decision.
Oleksiejczuk faced Shamil Gamzatov on October 30, 2021, at UFC 267. He won the bout via TKO in the first round.
Oleksiejczuk faced Dustin Jacoby on March 5, 2022, at UFC 272. He lost the fight via unanimous decision.
Oleksiejczuk faced Sam Alvey on August 6, 2022, at UFC on ESPN 40. He won the fight via technical knockout in round one.
Oleksiejczuk was scheduled to face Albert Duraev, replacing injured Bruno Silva, on December 17, 2022, at UFC Fight Night 216. In turn, Duraev was forced to withdraw for undisclosed reasons and was replaced by Cody Brundage. Oleksiejczuk won the fight via knockout in round one. This win earned him the Performance of the Night award.
Oleksiejczuk faced Caio Borralho on April 29, 2023, at . He lost the fight via rear-naked choke in round two.
Oleksiejczuk faced Chidi Njokuani at UFC Fight Night 225 on August 26, 2023. He won by first-round ground and pound technical knockout, which earned him a Performance of the Night award.
Oleksiejczuk faced Michel Pereira on March 9, 2024, at UFC 299. He lost the bout in the first round by rear-naked choke submission.
Oleksiejczuk faced Kevin Holland on June 1, 2024, at UFC 302. After knocking Holland down, Oleksiejczuk lost by an armbar submission in the first round.
Oleksiejczuk faced Sharabutdin Magomedov on August 3, 2024 at UFC on ABC 7. He lost the fight by unanimous decision. This fight earned him a Fight of the Night award.
Oleksiejczuk faced Sedriques Dumas on April 12, 2025 at UFC 314. He won the fight by technical knockout in the first round.
Oleksiejczuk faced Gerald Meerschaert on August 16, 2025, at UFC 319. He won the fight via technical knockout in round one.
Oleksiejczuk faced Marc-André Barriault on February 7, 2026, at UFC Fight Night 266. He won the fight by unanimous decision. This fight earned him a $100,000 Fight of the Night award.
Oleksiejczuk is married to his wife Ewelina they have 2 daughters together.
Oleksiejczuk has befriended his former opponent Caio Borralho. In 2025 Borralho invited him to the fighting nerds gym in Brazil to help him train for his fight at UFC 314. Since then Oleksiejczuk has continued to train with the fighting nerds.
|- |Win |align=center|22âÂÂ9 (1) |Marc-André Barriault |Decision (unanimous) | | |align=center|3 |align=center|5:00 |Las Vegas, Nevada, United States | |- |Win |align=center|21âÂÂ9 (1) |Gerald Meerschaert |TKO (punches) |UFC 319 | |align=center|1 |align=center|3:03 |Chicago, Illinois, United States | |- |Win |align=center|20âÂÂ9 (1) |Sedriques Dumas |TKO (punches and elbows) |UFC 314 | |align=center|1 |align=center|2:49 |Miami, Florida, United States | |- |Loss |align=center|19âÂÂ9 (1) |Sharabutdin Magomedov |Decision (unanimous) | | |align=center|3 |align=center|5:00 |Abu Dhabi, United Arab Emirates | |- |Loss |align=center|19âÂÂ8 (1) |Kevin Holland |Technical Submission (armbar) |UFC 302 | |align=center|1 |align=center|1:34 |Newark, New Jersey, United States | |- |Loss |align=center|19âÂÂ7 (1) |Michel Pereira |Technical Submission (rear-naked choke) |UFC 299 | |align=center|1 |align=center|1:01 |Miami, Florida, United States | |- |Win |align=center|19âÂÂ6 (1) |Chidi Njokuani |TKO (punches) | | |align=center|1 |align=center|4:16 |Kallang, Singapore | |- |Loss |align=center|18âÂÂ6 (1) |Caio Borralho |Submission (rear-naked choke) | | |align=center|2 |align=center|2:49 |Las Vegas, Nevada, United States | |- |Win |align=center|18âÂÂ5 (1) |Cody Brundage |KO (punches) | | |align=center|1 |align=center|3:16 |Las Vegas, Nevada, United States | |- |Win |align=center|17âÂÂ5 (1) |Sam Alvey |TKO (punches) | | |align=center|1 |align=center|1:56 |Las Vegas, Nevada, United States | |- |Loss |align=center|16âÂÂ5 (1) |Dustin Jacoby |Decision (unanimous) |UFC 272 | |align=center|3 |align=center|5:00 |Las Vegas, Nevada, United States | |- |Win |align=center|16âÂÂ4 (1) |Shamil Gamzatov |TKO (punches) |UFC 267 | |align=center|1 |align=center|3:31 |Abu Dhabi, United Arab Emirates | |- |Win |align=center|15âÂÂ4 (1) |Modestas Bukauskas |Decision (split) |UFC 260 | |align=center|3 |align=center|5:00 |Las Vegas, Nevada, United States | |- |Loss |align=center| |Jimmy Crute |Submission (kimura) | | |align=center|1 |align=center|3:29 |Auckland, New Zealand | |- |Loss |align=center|14âÂÂ3 (1) |Ovince Saint Preux |Submission (Von Flue choke) | | |align=center|2 |align=center|2:14 |Copenhagen, Denmark | |- |Win |align=center|14âÂÂ2 (1) |Gadzhimurad Antigulov |KO (punch) | | |align=center| 1 |align=center| 0:44 |Saint Petersburg, Russia | |- |Win |align=center|13âÂÂ2 (1) |Gian Villante |TKO (punches) | | |align=center| 1 |align=center| 1:34 |Prague, Czech Republic | |- |NC |align=center|12âÂÂ2 (1) |Khalil Rountree Jr. |NC (overturned) |UFC 219 | |align=center| 3 |align=center| 5:00 |Las Vegas, Nevada, United States | |- |Win |align=center|12âÂÂ2 |Riccardo Nosiglia |KO (punches) |Fight Exclusive Night 17 | |align=center| 1 |align=center| 1:40 |Gdynia, Poland | |- |Win |align=center|11âÂÂ2 |Charles Andrade |KO (punch) |Thunderstrike Fight League 11 | |align=center| 1 |align=center| 1:58 |Kraà Ânik, Poland | |- |Win |align=center|10âÂÂ2 |à Âukasz Klinger |TKO (punches) |Thunderstrike Fight League 10 | |align=center| 1 |align=center| N/A |Lublin, Poland | |- |Win |align=center|9âÂÂ2 |Wojciech Janusz |Decision (unanimous) |Fight Exclusive Night 12 | |align=center| 3 |align=center| 5:00 |Wrocà Âaw, Poland | |- |Win |align=center|8âÂÂ2 |à Âukasz Borowski |Submission (rear-naked choke) |Thunderstrike Fight League 8 | |align=center| 2 |align=center| 3:39 |Lublin, Poland | |- |Win |align=center|7âÂÂ2 |Michal Dobiaà ¡ |KO (kick to the body) |rowspan=2| Wenglorz Fight Cup 6 |rowspan=2| |align=center| 2 |align=center| N/A |rowspan=2|Lidzbark Warmià Âski, Poland | |- |Win |align=center|6âÂÂ2 |Andrejs Zozulja |KO (punches) |align=center| 1 |align=center| N/A | |- |Win |align=center|5âÂÂ2 |Tomasz Janiszewski |TKO (strikes) |Thunderstrike Fight League 7 | |align=center| 2 |align=center| 4:38 |Kraà Ânik, Poland | |- |Win |align=center|4âÂÂ2 |Seweryn Kirschhiebel |TKO (corner stoppage) |Thunderstrike Fight League 6 | |align=center| 2 |align=center| 2:25 |Lublin, Poland | |- |Loss |align=center|3âÂÂ2 |Marcin Wójcik |TKO (punches) |PLMMA 44 | |align=center| 1 |align=center| 2:12 |Bieà ¼uà Â, Poland | |- |Win |align=center|3âÂÂ1 |Norbert Piskorski |TKO (leg injury) |Thunderstrike Fight League 5 | |align=center| 1 |align=center| N/A |Lublin, Poland | |- |Loss |align=center|2âÂÂ1 |Jan Kwiatoà  |Submission (triangle choke) |Thunderstrike Fight League 4 | |align=center| 1 |align=center| 1:53 |à ÂÃÂczna, Poland | |- |Win |align=center|2âÂÂ0 |Mateusz Gola |Decision (unanimous) |Tymex Fight Night | |align=center| 3 |align=center| 5:00 |Pionki, Poland | |- |Win |align=center|1âÂÂ0 |Rajmund Flejmer |Decision (unanimous) |Vale Tudo Cup 1 | |align=center| 2 |align=center| 5:00 |Puà Âawy, Poland | |-