The SAIL Dementia e-Cohort is a population-based electronic cohort (e-cohort) containing health-related information on people with and without diagnosed dementia. By applying coding algorithms to linked routinely-collected datasets, a novel Dementia Platform UK (DPUK) cohort was developed to maximise generalisability and utility for a broad range of research questions and methodologies. It aims to minimise duplication of effort, increase reproducibility, reduce costs, and allow a broader range of researchers to apply to use SAIL data.