Cognitive decline has significant health, economic and social consequences on individuals and society, and there is evidence that financial adversity – even in the short term – might play some role in this. However, little is known on the long-term effect of persistence exposure to financial adversity on cognitive ageing. Using data from the 1946 Birth cohort study and an embedded neuroimaging study (Insight46), we will examine the impact of persistent financial adversity across adulthood on cognitive decline and markers for brain health in older age. We will also test for the moderating effect of sex, childhood socioeconomic circumstances and genetic risk for dementia, to explore whether these additional biological and environmental factors may exacerbate the effect of persistent financial adversity on cognitive ageing.