The main aim of this article is to present a research agenda and systematic framework of what the field of health information systems is about, namely its central topics and connecting areas. In doing so, we try to provide a cohesive 'big picture' for academics and professionals that are interested in conducting research in this broad area. By using a large number of disparate data sources, we identified 3 major research fields and 18 sub-fields. As this discipline is quite new and heterogeneous in terms of themes and the educational backgrounds of its researchers, we see our conceptualisation as a first step in obtaining a collective understanding of this field, as well as being a common starting point for discussing future directions.