Objective: To assess trends in service use and outcome of critically ill older people (aged = 65 years) admitted to an intensive care unit (ICU). Design, patients and setting: Retrospective cohort analysis of administrative data on older patients discharged from ICUs at all 23 adult public hospitals with onsite ICUs in Victoria between 1 July 1999 and 30 June 2011. Subgroups examined included those aged = 80 years, major diagnosis categories, and those receiving mechanical ventilation. Main outcome measures: Resource use and hospital survival; also length of stay (LOS) and discharge destination trends. Results: Over 12 years, 108 171 people aged = 65 years were admitted to ICUs; of these, 49 912 (46.1 ) received mechanical ventilation and 17 772 (16.4 ) died. Despite an increase in the older age population (2.5 per annum) and acute care admissions (7.3 per annum) over the period studied, there was a net reversal in prevalence trends for ICU admissions (-1.7 per annum; P = 0.04) and admissions of patients requiring mechanical ventilation (-1.6 per annum) in the 8 years since 2004. Annual risk-adjusted mortality fell (odds ratio, 0.97 per year; 95 CI, 0.96-0.97 per year; P <0.001) without prolongation of hospital or ICU LOS (P = 0.49) or discharge to residential aged care (RAC). Similar trends were noted in all a priori subgroups. Conclusions: Improved hospital survival without an increase in demand for ICU admission or RAC or an increase in LOS suggests there has been improvement in the care of the older age population.