S.O.S. Antwerp (Sociale Ongelijkheid in Sterfte) is a citizen science project financed by the Flemish Government. Its aim is to create and analyse a high-quality database of causes of death of the Antwerp population based on a unique individual-level cause-of-death register preserved in the Antwerp City Archives. Once finished, the database will contain the causes of death of all persons who died in Antwerp in the period 1820-1946. As such, it will become possible to map the spatio-temporal history of disease, but also to reconstruct social (in)equalities in death in the city of Antwerp for over more than a century. By involving the general public in its construction and by collaborating with research scholars, S.O.S. Antwerp wants to enable participants to make a direct contribution to research, increase their scientific understanding of the history of public health and the historical roots of inequalities in health.