| Res. | Record | Opponent | Method | Event | Date | Round | Time | Location | Notes |
| Win | 16–7 | Thiago Santos | Decision (unanimous) | PFL vs. Bellator | February 24, 2024 | 3 | 5:00 | Riyadh, Saudi Arabia | |
| Loss | 15–7 | Vadim Nemkov | Decision (unanimous) | Bellator 297 | June 16, 2023 | 5 | 5:00 | Chicago, Illinois, United States | For the Bellator Light Heavyweight World Championship. |
| Win | 15–6 | Melvin Manhoef | KO (elbows) | Bellator 285 | September 23, 2022 | 3 | 3:34 | Dublin, Ireland | |
| Win | 14–6 | Alex Polizzi | TKO (punches) | Bellator 280 | May 6, 2022 | 3 | 4:59 | Paris, France | |
| Loss | 13–6 | Phil Davis | Decision (split) | Bellator 266 | September 18, 2021 | 3 | 5:00 | San Jose, California, United States | Return to Light Heavyweight. |
| Loss | 13–5 | Israel Adesanya | Decision (unanimous) | UFC 248 | March 7, 2020 | 5 | 5:00 | Las Vegas, Nevada, United States | For the UFC Middleweight Championship. |
| Loss | 13–4 | Paulo Costa | Decision (unanimous) | UFC 241 | August 17, 2019 | 3 | 5:00 | Anaheim, California, United States | Fight of the Night. |
| Loss | 13–3 | Robert Whittaker | Decision (split) | UFC 225 | June 9, 2018 | 5 | 5:00 | Chicago, Illinois, United States | Non-title bout; Romero missed weight (185.2 lb). Fight of the Night. |
| Win | 13–2 | Luke Rockhold | KO (punches) | UFC 221 | February 11, 2018 | 3 | 1:48 | Perth, Australia | For the interim UFC Middleweight Championship. Romero missed weight (187.7 lb) and was ineligible for the title. |
| Loss | 12–2 | Robert Whittaker | Decision (unanimous) | UFC 213 | July 8, 2017 | 5 | 5:00 | Las Vegas, Nevada, United States | For the interim UFC Middleweight Championship. Fight of the Night. |
| Win | 12–1 | Chris Weidman | KO (flying knee) | UFC 205 | November 12, 2016 | 3 | 0:24 | New York City, New York, United States | Performance of the Night. |
| Win | 11–1 | Ronaldo Souza | Decision (split) | UFC 194 | December 12, 2015 | 3 | 5:00 | Las Vegas, Nevada, United States | |
| Win | 10–1 | Lyoto Machida | KO (elbows) | UFC Fight Night: Machida vs. Romero | June 27, 2015 | 3 | 1:38 | Hollywood, Florida, United States | Performance of the Night. |
| Win | 9–1 | Tim Kennedy | TKO (punches) | UFC 178 | September 27, 2014 | 3 | 0:58 | Las Vegas, Nevada, United States | Fight of the Night. |
| Win | 8–1 | Brad Tavares | Decision (unanimous) | UFC on Fox: Werdum vs. Browne | April 19, 2014 | 3 | 5:00 | Orlando, Florida, United States | |
| Win | 7–1 | Derek Brunson | TKO (punches and elbows) | UFC Fight Night: Rockhold vs. Philippou | January 15, 2014 | 3 | 3:23 | Duluth, Georgia, United States | Fight of the Night. |
| Win | 6–1 | Ronny Markes | KO (punches) | UFC: Fight for the Troops 3 | November 6, 2013 | 3 | 1:39 | Fort Campbell, Kentucky, United States | |
| Win | 5–1 | Clifford Starks | KO (flying knee and punches) | UFC on Fox: Henderson vs. Melendez | April 20, 2013 | 1 | 1:32 | San Jose, California, United States | Middleweight debut. Knockout of the Night. |
| Loss | 4–1 | Rafael Cavalcante | KO (punches) | Strikeforce: Barnett vs. Kharitonov | September 10, 2011 | 2 | 4:51 | Cincinnati, Ohio, United States | |
| Win | 4–0 | Laszlo Eck | KO (punch) | Fight of the Night 2011 | May 27, 2011 | 1 | 0:33 | Greding, Germany | |
| Win | 3–0 | Ņikita Petrovs | TKO (retirement) | Superior FC 4 | March 5, 2011 | 1 | 2:58 | Giessen, Germany | |
| Win | 2–0 | Michał Fijałka | TKO (retirement) | Infinite Fighting Federation: The Eternal Struggle | October 8, 2010 | 3 | 4:05 | Dąbrowa Górnicza, Poland | |
| Win | 1–0 | Sascha Weinpolter | TKO (punches) | Fight of the Night 2009 | December 20, 2009 | 1 | 0:48 | Nuremberg, Germany | Light Heavyweight debut. |