This study aims to evaluate the effect of hyperbaric oxygen therapy (HBOT) on the amputation level in patients undergoing fasciotomy with a Mangled Extremity Severity Score (MESS) score of ≥7 after 2023 Kahramanmaras earthquake. Between February 6th, 2023 and March 10th, 2023, a total of 23 patients (14 males, 9 females; mean age: 36.8±13.2 years; range, 17 to 64 years) who needed amputation with a MESS score of ≥7 and refused amputation were included in the study. All fasciotomies were performed in an external center, and five of them was incomplete. First, incomplete fasciotomies were completed with debridement due to deep muscle necrosis. Daily two HBOT sessions were performed for the first three days. In the following days, daily one HBOT session was performed. The HBOT was terminated for the patients who were decided by the council that they did not benefit from HBOT treatment. Six (26.08%) of the patients had a bone fracture (n=2 forearm, n=1 femur, n=2 tibia, and n=1 ankle fracture). The mean number of HBOT session was 13.24±5.4 (range, 7 to 30) and the mean duration of HBOT was 26.5±10.8 (range, 14 to 60) h. The mean MESS score was 9.96±1.36 (range, 7 to 12). All of the patients were trapped under the rubble with a mean time of 12.3±5.4 (range, 6 to 23) h. All fasciotomies were performed within the first 30 h. Twenty-two of the patients were amputated at the level previously determined by the experienced trauma surgeons. The amputation level changed in only one patient. After 38 h of HBOT, transradial amputation was performed to the patient in whom transhumeral amputation level was determined previously. None of the patients had any adverse event related to HBOT. Our study results suggest that the MESS is a useful scoring system for amputation decision after a high-energy trauma, such as an earthquake, with a high accuracy rate. The outcomes of HBOT are not satisfactory for high-energy traumas, such as earthquakes, in those requiring fasciotomy having more muscle necrosis and a MESS score of ≥7.