Introduction: Major trauma describes serious and often multiple injuries where there is a strong possibility of death or residual disability. There is little robust evidence on the effects of embedded rehabilitation within the trauma care pathway. Trauma rehabilitation services therefore remain fragmented and poorly integrated. This study aimed to determine changes in hospital length of stay (LoS), intensive care unit (ICU) LoS, 30-day mortality and Glasgow Outcome Scale following implementation of an embedded rehabilitation service into a Major Trauma Centre (MTC). Methods: Retrospective pre-post observational study of a rehabilitation service introduced into an MTC, consisting of a dedicated 10-bedded inpatient unit, co-ordinating rehabilitation hub, and specialist multi-disciplinary outpatient clinic. Overall hospital LoS, ICU LoS, 30-day mortality and GOS were selected as outcome measures. Patient characteristics (age, sex, injury mechanism, injury severity score, Glasgow Coma Scale, and most injured body region) were compared and controlled for when analysing outcomes. Results: The study cohort included 6,484 patients, of which 4,298 were pre-intervention and 2,186 post-intervention. Patients in the post-intervention cohort were older than those in the pre-intervention cohort (58.3 compared to 56.6, p<0.001) and had higher injury severity scores (48.7% >15 compared to 43.9% >15). Moderate but significant changes to the most injured body region were also observed (p<0.001), with fewer injuries affecting the limbs (25.8% to 24.9%), spine (15.3% to 12.1%), multiple locations (11.3% to 10.7%), abdomen (2.7% to 2.4%) and face/other (1.9% to 1.5%) and more injuries affecting the head (27.5% to 31.5%) and chest (15.6% to 16.9%). Controlling for changes to patient characteristics between the two time periods, there was a reduction in overall hospital LoS of 2.56 days (b=-2.56, p<0.001) and ICU LoS of 0.94 days (b=-0.96, p<0.001). There was a 31% reduced chance of 30-day mortality in post-intervention patients (OR=0.69, 95%CI=0.54 to 0.88), and almost two times higher relative chance of GOS Good Recovery (RR=1.94, CI=1.51 to 2.49). Discussion: Embedded rehabilitation is an important and necessary component of an effective trauma system that is associated with improved service and patient outcomes. Future research should examine prospectively how a dedicated rehabilitation service affects medium- and long-term patient-centred outcomes.