BACKGROUND: The aging global population forecasts a significant rise in severe trauma cases among individuals aged 65 and above. Frailty emerges as a paramount predictor of post-traumatic outcomes, surpassing age and trauma severity indices. Despite this, scant attention is given to the trajectory of elderly patients post-intensive care unit (ICU) stay following severe trauma, justifying this study. The objective of this study was to analyze trajectories (frailty, place of residence) following a major trauma requiring an ICU stay. MATERIALS AND METHODS: An observational cohort study was conducted, leveraging data from a level 1 trauma center spanning 2018 to 2023. Inclusion criteria included elderly patients aged 65 and above admitted to the ICU for severe trauma. Data encompassed demographic profiles, trauma severity scores, clinical parameters, and frailty assessments sourced from the Traumabase database. RESULTS: Among 293 patients included 190 were non-frail, frailty was correlated with elevated mortality rates (114 (38.9%) at 6 months), heightened incidence of traumatic brain injuries, and notable declines in post-traumatic autonomy. Only 39.2% of patients had resumed residence at home six months post-injury, with a conspicuous trend towards institutionalization, particularly among frail individuals. CONCLUSION: This study highlights the role of frailty in determining the outcomes of elderly patients following severe trauma. Frailty is associated with higher mortality, increased rates of institutionalization, and a decline in functional status. These results highlight the importance of assessing frailty in the trajectory of severely injured patients over the age of 65 years-old.