Cohort Studies of Memory in an International Consortium, or COSMIC, is an international consortium that combines data from population-based longitudinal cohorts studies to identify common risk factors for dementia and cognitive decline. It is an Australian-led collaboration by the Centre for Healthy Brain Ageing (CHeBA) at UNSW Sydney, Australia, and is funded by the National Institutes of Health, USA. There are currently 59 member studies from 39 countries from six continents. COSMIC facilitates a better understanding of the determinants of cognitive ageing and neurocognitive disorders.