Marcin Prachnio

Ultimate Fighting Championship The successful run in the ONE FC resulted in a contract with the UFC in 2018. In his promotional debut he faced Sam Alvey on February 24, 2018 at UFC on Fox 28. He lost the fight via knockout in the first round.

In his sophomore bout in the organization, Prachnio faced Magomed Ankalaev on September 15, 2018 at UFC Fight Night: Hunt vs. Oleinik. He lost the bout via knockout in the first round.

Prachnio faced Mike Rodríguez on August 22, 2020 at UFC on ESPN 15. He lost the fight via knockout in the first round.

Prachnio faced Khalil Rountree Jr. on January 24, 2021 at UFC 257. He won the fight via unanimous decision.

Prachnio faced Ike Villanueva on June 26, 2021 at UFC Fight Night 190. He won the fight via knockout out in round two. This fight earned him the Performance of the Night award.

Prachnio was scheduled to face Azamat Murzakanov on November 20, 2021 at UFC Fight Night 198. However, the bout was later scrapped due to visa issues.

Prachnio faced Philipe Lins on April 23, 2022 at UFC Fight Night 205. He lost the fight via unanimous decision.

Prachnio was scheduled to face William Knight on November 19, 2022, at UFC Fight Night 215. However, the bout was scrapped the week of the event for undisclosed reasons. The bout was rescheduled for UFC Fight Night 219 on February 18, 2023. He won the fight via unanimous decision.

Prachnio faced Vitor Petrino on July 8, 2023, at UFC 290. He lost the fight via an arm-triangle choke submission in the third round.

Prachnio faced Devin Clark on February 10, 2024, at UFC Fight Night 236. He won the bout by unanimous decision.

Prachnio faced Modestas Bukauskas on July 27, 2024, at UFC 304. He lost the fight by an arm-triangle choke submission in the third round.

Prachnio was scheduled to face Jimmy Crute on February 9, 2025, at UFC 312. However, Prachnio withdrew from the fight for unknown reasons and was replaced by Rodolfo Bellato.

Prachnio's bout with Jimmy Crute was re-scheduled and took place on July 19, 2025 at UFC 318. He lost the fight via an armbar submission at the end of the first round.

On December 16, 2025, it was reported that Prachino was released by the UFC.

Championships and accomplishments Mixed martial arts Ultimate Fighting Championships Performance of the Night (One time)

Mixed martial arts record Loss

Tom Breese Submission (rear-naked choke) FNC 32

Osijek, Croatia Loss

Jimmy Crute Submission (armbar) UFC 318

New Orleans, Louisiana, United States Loss

Modestas Bukauskas Submission (arm-triangle choke) UFC 304

Manchester, England Win

Devin Clark Decision (unanimous) UFC Fight Night: Hermansson vs. Pyfer

Las Vegas, Nevada, United States Loss

Vitor Petrino Submission (arm-triangle choke) UFC 290

Las Vegas, Nevada, United States Win

William Knight Decision (unanimous) UFC Fight Night: Andrade vs. Blanchfield

Las Vegas, Nevada, United States Loss

Philipe Lins Decision (unanimous) UFC Fight Night: Lemos vs. Andrade

Las Vegas, Nevada, United States Win

Ike Villanueva KO (body kick) UFC Fight Night: Gane vs. Volkov

Las Vegas, Nevada, United States Win

Khalil Rountree Jr. Decision (unanimous) UFC 257

Abu Dhabi, United Arab Emirates Loss

Mike Rodríguez KO (elbow and punches) UFC on ESPN: Munhoz vs. Edgar

Las Vegas, Nevada, United States Loss

Magomed Ankalaev TKO (head kick and punches) UFC Fight Night: Hunt vs. Oleinik

Moscow, Russia Loss

Sam Alvey KO (punch) UFC on Fox: Emmett vs. Stephens

Orlando, Florida, United States Win

Gilberto Galvão KO (punch) ONE: Kings & Conquerors

Macau, SAR, China Win

Jake Butler TKO (knees) ONE: Titles & Titans

Jakarta, Indonesia Win

Leandro Ataides Decision (split) ONE: Kingdom of Champions

Bangkok, Thailand Win

Alexandre Machado TKO (punches) ONE: Tribe of Warriors

Jakarta, Indonesia Win

Tomislav Spahović TKO (punches) Final Fight Championship 21

Rijeka, Croatia Win

Matej Batinić Decision (unanimous) Final Fight Championship 19

Linz, Austria Win

Ryan Salamagnou TKO (punches) HIT Fighting Championship 1

Zürich, Switzerland Win

Elvir Cosic TKO (punches) Bosnian Fight Championship 2

Sarajevo, Bosnia and Herzegovina Loss

Aleksandar Rakić TKO (punches) Final Fight Championship 16

Vienna, Austria Win

Stepjan Bekavac TKO (knees) Final Fight Championship 14

Ljubljana, Slovenia Win

Milco Voorn TKO (punches) Fight Club Den Haag 2014

The Hague, Netherlands Win

Bozo Mikulic TKO (punches) Final Fight Championship 13

Zadar, Croatia Loss

Ivica Tadijanov Decision (unanimous) Final Fight Championship 11

Osijek, Croatia Win

Milan Vinčić Submission (rear-naked choke) Bosnian Fight Championship 1

Sarajevo, Bosnia and Herzegovina Win

Tomas Siaucila KO (punch) Ultimate Warrior Challenge 23

Essex, England