Background: Chest injury was found to cause death in 20%–25% of multiple trauma patients. Thoracic trauma is, therefore, important in the overall management of multiple injury patients and may require a longer stay in the Intensive Care Unit (ICU) and use of mechanical ventilation. Methods: This prospective randomized clinical study was in Emergency Intensive Care, Tanta University Hospitals. For, 88 adult patients with blunt chest injury. Patients were enrolled in this study aged ≥18 years old classified into two equal groups: Group I (Non-Invasive Mechanical Ventilation group) = 44 patient: Patients in this group received BIPAP. Group II (Control group=44 patient: Patients in this group have received high flow O2 by mask O2 without use of non-invasive mechanical ventilation. Data of collection were: the demographic data, Frequent arterial blood gas analysis of all patients every 6 hrs. Respiratory rate, Arterial blood pressure, Heart rate were recorded: every 6 h. All Patients receive analgesia. Evaluate outcome: a-Primary outcome. Tracheal intubation, duration of ventilation. b-Secondary outcome. Mortality, ICU length stay. And Chest Trauma Scoring System. Results: Ten patients (22%) were intubated and mechanically ventilated in group I (BiPAP). with mean value of duration of ventilation 34.4 hrs. But at group II 16   patients (36%) were intubated and mechanically ventilated with mean value of duration of ventilation 34.12 hrs. ICU stay at group I (BiPAP) was statistically decrease of number of days when compared to group II (control). 6 days at group I and 12 days at group II. In this study no case of mortality was recorded with non-invasive ventilation, although three mortality cases were recorded with the control group. Conclusion: This study recommends the pre-emptive use of Non-Invasive Ventilation in the treatment for blunt chest injury in patients at risk for respiratory failure. Success of Non-Invasive Ventilation depends on improvement of hypercarbia and hypoxemia in patients impending respiratory failure due to reversible cause as blunt chest trauma with the expectation of a good outcome and avoidance of intubation.