Intrinsic Capacity (IC) is a comprehensive, strength-based measure of capacity in older individuals, central to the World Health Organization’s healthy ageing framework. While IC has been shown to predict key outcomes such as functional decline, mortality, and dementia, no study has explored population-level trends in Australia. Our study addresses this gap by estimating IC in the Household, Income and Labour Dynamics in Australia (HILDA) Survey, a large, nationally representative[KH1.1] longitudinal dataset. Our sample comprises 43,087 observations from 6026 participants aged 65 and older, spanning 13 waves collected between 2012 and 2024. IC is first estimated at an individual level using Confirmatory Factor Analysis, then analysed using mixed-effect models to examine trends by birth cohort and socioeconomic status. Finally, we use Structural Equation Modelling to assess IC as a predictor of healthcare utilisation including hospitalizations, prescription medication use, and GP visits. We provide the first population-representative estimates of IC in Australia, identify systematic differences across birth cohorts and socioeconomic groups[KH2.1], and evaluate its viability as a tool for predicting health service demand. Preliminary findings suggest IC has declined between successive birth cohorts, alongside substantial socioeconomic inequalities, particularly among renters, individuals with low asset values, and those with lower educational attainment. Our findings demonstrate the value of IC as a population health metric and its potential to inform health system planning. By linking these results to future health service demand, our research provides policymakers, health planners, and practitioners with valuable insights into the evolving health and needs of Australia’s older population.