The national population-based cohort study EpiCov (Epidemiology and Living Conditions during COVID-19) was conducted by the French National Institute of Health and Medical Research (INSERM) and the French Directorate for Research, Studies, Evaluation, and Statistics (DREES) in collaboration with Santé Publique France and INSEE, the National Institute of Statistics and Economics Studies. A sample of 371,000 people was randomly selected from the Fidéli national demographic register of individuals and households produced by INSEE. Four waves occurred in May 2020, November 2020, June 2021, and October 2022. Data combined a questionnaire survey administered by telephone or online with COVID-19 serological tests performed on self-administered blood samples. EpiCov provided a wealth of information for statistics and public health research, as much from a methodological viewpoint as from the diversity and the multidisciplinary character of the themes under study.