The Canadian Study of Health and Aging collected data focusing on the epidemiology of dementia, using interviews and questionnaires, clinical and neuropsychological examinations, physical measurements and blood collection, and access to public records such as death certificates, from people 65 and over in community (N = 9,008) institutional settings (N = 1,255). The study produced 12 data sets, including community health interviews, clinical and neuropsychological assessments, risk factor questionnaires, and caregiver interviews. This report describes the data collection and processing procedures, summarizes the content of each data set, and outlines the information collected in sufficient detail to permit its suitability for secondary analyses to be scrutinized.