Background: mid-face fracture is the most common type in maxillofacial trauma. Inflammation of maxillary sinus post-trauma is a late complication and usually be skipped after surgery of rigidifying and reconstructing of maxillary sinus. The research objects to evaluate this complication in the mid-face trauma patients with maxillary sinus injury after being treated by sinonasal endoscopic surgery. Method: 55 patients with mid-face trauma having maxillary sinus injury hospitalized in Thu Duc district Hospital from 09/2009 to OS/2012 were treated by endoscopic sinonasal surgery were evaluated for the inflammation of the maxillary sinus using clinical, endoscopic and CT scans criteria. Results: the incidence of inflammation of maxillary sinus was 1,82 percent (1 case). There was an improvement post-surgery from 2 weeks to 3 months of clinical features, sinonasal endoscopy and cr scan imaging. After 3 months of surgery, almost the patients relieve from symptoms of rhinosinusitis. Conclusion: patients with midface trauma involving the maxillary sinus had lower incidence of inflammation of maxillary sinus post-surgery after being treated by sinonasal endoscopic surgery. This method will become an effective method for management of mid-face trauma with maxillary sinus injury.