BACKGROUND:: The aim of the study was to quantify trauma-related mortality in injured adults over 10 years postinjury. METHODS:: A population-based matched cohort study used linked administrative data from Manitoba, Canada, to identify an inception cohort (1988-1991) of hospitalized trauma cases (ICD-9-CM 800-959.9) aged 18-64 years (n = 18,210) and a matched noninjured comparison group (n = 18,210). Mortality outcomes were obtained by linking the two cohorts with the Manitoba Population Registry for a period of 10 years postinjury. RESULTS:: The adjusted all-cause mortality rate ratio (MRR) was 7.29 (95% CI 4.53-11.74) for the 60 days immediately postinjury. The MRRs ranged between 1.17 and 2.41 for the remainder of the 10 year follow-up period. The index injury was estimated to be responsible for 41% of all recorded deaths in the injured cohort. CONCLUSIONS:: Estimates of the total mortality burden, based on the early inpatient period alone, substantially underestimates the true burden from injury.