Background. Airway management remains a fundamental component of optimal care of the severely injured patient, with endotracheal intubation representing the definitive strategy for airway control. However, multiple studies document an association between out-of-hospital intubation and increased mortality for severe traumatic brain injury. Objectives. To explore the relationship between out-of-hospital intubation attempts and outcome among trauma patients with Glasgow Coma Scale (GCS) scores ≤8 across sites participating in the Resuscitation Outcomes Consortium (ROC). Methods. The ROC Epistry-Trauma, an epidemiologic database of prehospital encounters with critically injured trauma victims, was used to identify emergency medical services (EMS)-treated patients with GCS scores ≤8. Multiple logistic regression was used to explore the association between intubation attempts and vital status at discharge, adjusting for the following covariates: age, gender, GCS score, hypotension, mechanism of injury, and ROC site. Sites were then stratified by frequency of intubation attempts and chi-square test for trend was used to associate the frequency of intubation attempts with outcome. Results. A total of 1,555 patients were included in this analysis; intubation was attempted in 758 of these. Patients in whom intubation was attempted had higher mortality (adjusted odds ratio [OR] 2.91, 95% confidence interval [CI] 2.13-3.98, p < 0.01). However, sites with higher rates of attempted intubation had lower mortality across all trauma victims with GCS scores ≤8 (OR 1.40, 95% CI 1.15-1.72, p < 0.01). Conclusions. Patients in whom intubation is attempted have higher adjusted mortality. However, sites with a higher rate of attempted intubation have lower adjusted mortality across the entire cohort of trauma patients with GCS scores ≤8. Key words: prehospital intubation; traumatic brain injury; airway management; paramedic; outcomes; major trauma victim; ventilation; mortality; Glasgow Coma Scale score © 2011 National Association of EMS Physicians.