AbstractObjectiveTo describe the frequency of hospitalisation and in‐hospital death following moderate to severe traumatic brain injury (TBI) in Australia, both overall and by patient demographic characteristics and the nature and severity of the injury.Design, settingCross‐sectional study; analysis of Australia New Zealand Trauma Registry data.ParticipantsPeople with moderate to severe TBI (Abbreviated Injury Score [head] greater than 2) who were admitted to or died in one of the twenty‐three major Australian trauma services that contributed data to the ATR throughout the study period, 1 July 2015 – 30 June 2020.Major outcome measuresPrimary outcome: number of hospitalisations with moderate to severe TBI; secondary outcome: number of deaths in hospital following moderate to severe TBI.ResultsDuring 2015–20, 16 350 people were hospitalised with moderate to severe TBI (mean, 3270 per year), of whom 2437 died in hospital (14.9%; mean, 487 per year). The mean age at admission was 50.5 years (standard deviation [SD], 26.1 years), and 11 644 patients were male (71.2%); the mean age of people who died in hospital was 60.4 years (SD, 25.2 years), and 1686 deaths were of male patients (69.2%). The overall number of hospitalisations did not change during 2015–20 (per year: incidence rate ratio [IRR], 1.00; 95% confidence interval [CI], 0.99–1.02) and death (IRR, 1.00; 95% CI, 0.97–1.03).ConclusionInjury prevention and trauma care interventions for people with moderate to severe TBI in Australia reduced neither the incidence of the condition nor the associated in‐hospital mortality during 2015–20. More effective care strategies are required to reduce the burden of TBI, particularly among younger men.