The national population-wide cohort study, Epicov (Epidemiology and Living Conditions under COVID-19), was conducted by the National Institute of Health and Medical Research (Inserm) and the Directorate for Research, Studies, Evaluation, and Statistics (Drees), in collaboration with the National Institute of Statistics and Economic Studies (INSEE) and Santé publique France. A sample of 371,000 people was randomly selected from INSEE’s demographic databases on housing and individuals (Fidéli). Four survey waves took place in May 2020, November 2020, June 2021, and October 2022. Data were collected using a questionnaire administered by telephone or online, supplemented by a self-administered serological test performed at home. Epicov thus constitutes a valuable resource for research and public statistics, both from a methodological perspective and due to the diversity and multidisciplinary nature of the topics addressed.