Given that integrated care includes many different aspects, a study of how integration of care can be best be developed calls for an equally integrated research approach.The CORTEXS research project on integrated care in Flanders (Belgium) has developed a research design that takes (part of) this multi-facetedness and complexity into account.The research design involves multiple disciplines, levels of analysis, and methods.(1) The multidisciplinary research team combines expertise in organization sciences (including sociology, management and social innovation) with proficiency in care-specific disciplines (including care quality and safety, medical law, health economics and patient participation).(2) Integrated care is studied from the micro-level of care recipients and their informal caregivers, over the meso-level of intra-and inter-organizational processes, to the macro-level of legal and financial frameworks.(3) At each level, the most appropriate research methods are applied, including document analysis, process mapping, network analysis, comparative case analysis and economic modeling.The research comprises five work packages (WPs), each aimed at a specific research question: (WP1) Which models of integrated care for chronic and long term care needs can be found in the literature, and how can they be used for the further development of integrated care in the Flemish context?(WP2) What are the organizational components of integrated care models, and which options do they offer for supporting patient interests and quality of work for the health professionals?(WP3) What are the