Backround: Thoracic trauma causes life-threatening organ injuries, ranging from simple abrasions to contusions of intrathoracic organs. In this study, we aimed to investigate the effects of bosentan on endothelin-1 (ET-1), hypoxia-inducible factor-1 (HIF-1), nuclear factor-kappa B (NF-κB), tumor necrosis factor (TNF)-α as inflammation markers, pro-oxidant antioxidant balance (PAB) and total antioxidant capacity (TAC) levels as oxidative stress parameters in lung tissues of rats in experimental model of pulmonary contusion (PC) induced by blunt thoracic trauma. Methods: Thirty-seven animals male Sprague-Dawley rats were divided into 5 groups. All 4 groups, except for the control group, were performed to PC. In the first group, C: control group (n=6) consisted of unprocessed and untreated. The second group, PC3 (n=8) underwent of 3 days PC performed. The third group, PC-B3 (n=8) received 100 mg/kg bosentan was given orally once a day for 3 days. The fourth group, PC7 group (n=7) underwent of 7 days PC performed, and the fifth group PC-B7 (n=8) received 100 mg/kg bosentan was given orally once a day for 7 days. While ET-1, NF-B, TNF-, and HIF-1 was measured by ELISA method, TAC and PAB by spectrophotometric in lung tissue samples. Results: ET-1, NF-B, TNF-, HIF-1, and PAB levels were higher, while TAC activities were lower in all groups compared with the control (p < 0.05). There was no significant difference in ET-1 and TNF-- levels between the PC-B3 and PC-B7 groups and the control group (p < 0.05) while NF-B, HIF-1, and PAB levels were still higher in both the PC-B3 and PC-B7 groups than in the control group. Bosentan treatment causes decreased ET-1, NF-B, TNF-, HIF-1, and PAB and increased TAC levels in comparison to the nontreated groups (p < 0.05). Conclusions: We found that the use of bosentan decreased the severity of oxidative stress in the lung and reduced the inflammatory reaction in rats with PC induced by blunt thoracic trauma. This suggests that bosentan may have protective effects on lung injury mechanisms by reducing hypoxia, inflammation and oxidative stress. If supported by similar studies, bosentan can be used in both pulmonary and emergency clinics to reduce ischemic complications, inflammation, oxidative stress in some diseases that may be accompanied by ischemia.