Abstract This project will provide rigorous scientific evidence on the effects, over the long-term, of exposure to stressors on cognitive performance, physical and psychosocial health and well- being of older adults in Indonesia using extremely rich population-representative longitudinal data collected from about 12,000 older respondents (>40y) before and for 20 years after the 2004 Indian Ocean earthquake and tsunami, the Study of the Tsunami Aftermath and Recovery (STAR). The tsunami was a large and unanticipated natural disaster that devastated some coastal communities while other comparable, nearby communities were untouched because of the wave direction, land and seabed topography. Exposure to the tsunami is, therefore, plausibly exogenous in our study area, coastal Aceh and North Sumatra, so that estimated effects of exposure to the stress of the tsunami can be given a causal interpretation. We will investigate how these effects vary with the nature of individual-specific experiences of the tsunami including being caught up in the water, losing family and loss of economic livelihoods. The research will document the extent of resilience and recovery among older adults in the face of the tsunami and its aftermath, as well as the role played in these processes by individual, household, family and community resources, including post-tsunami reconstruction. Special attention is paid to the measurement and interpretation of cognition and health. All older respondents will complete assessments used to screen for Alzheimer's disease which will be clinically validated. For a randomly selected sub-sample of older respondents, the screeners will be complemented with innovative neuroscience-based measures of executive functioning and emotional control assessed on tablets in the home. Validated cardio-metabolic biological risks will be collected for the same subsample of older adults to provide uniquely rich, high quality measures of key outcomes designed for this research. The links between cognition and health will be described using contemporaneous measures and exploiting longitudinal data on health that reach back 15 years.