Often the clinician is faced with a diagnostic and therapeutic dilemma in patients with concomitant traumatic brain injury (TBI) and hemorrhagic shock (HS), as rapid deterioration from either can be fatal. Knowledge about outcomes following concomitant TBI and HS may help prioritize the emergent management of these patients. We hypothesized that patients with concomitant TBI and HS (TBI+HS) had worse outcomes and required more intensive care compared to patients with only one of these injuries.This is a post-hoc analysis of the Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial. TBI was defined by a head abbreviated injury scale >2. HS was defined as a base excess ≤ -4 and/or shock index ≥ 0.9. The primary outcome for this analysis was mortality at 30 days. Logistic regression, using generalized estimating equations (GEE), was used to model categorical outcomes.670 patients were included. Patients with TBI+HS had significantly higher lactate (median 6.3; IQR 4.7,9.2) compared to the TBI group (median 3.3; IQR 2.3,4). TBI+HS patients had higher activated prothrombin times and lower platelet counts. Unadjusted mortality was higher in the TBI+HS (51.6%) and TBI (50%) groups compared to the HS (17.5%) and neither group (7.7%). Adjusted odds of death in the TBI and TBI+HS groups were 8.2 (95% CI, 3.4-19.5) and 10.6 (95% CI, 4.8-23.2) times higher, respectively. Ventilator, ICU- and hospital-free days were lower in the TBI and TBI+HS groups compared to the other groups. Patients with TBI+HS or TBI had significantly greater odds of developing a respiratory complication compared to the neither group.The addition of TBI to HS is associated with worse coagulopathy prior to resuscitation, and increased mortality. When conrolling for multiple known confounders, the diagnosis of TBI alone or TBI+HS was associated with significantly greater odds of developing respiratory complications.prognostic study LEVEL OF EVIDENCE: II.