Introduction: Coordination between levels of care is not facilitated in the Belgian health system. Indeed, patients have uninhibited access to every level of care, there is no gatekeeping system, and few structural coordination between levels of care. On one hand, the occurrence of more complex care situations in the ambulatory setting is enhancing the need for coordination while on the other hand, hospitals face financial constraints to provide care in the community.Implementation: The aim of the research was to organize coordination between levels of care at the local level, in an urban setting. We used the “Local Health System” model (LHS) that aims at integrating hospital and primary care activities for a defined population at the local level. We chose the participatory action research (PAR) methodology and its spiral plan-do-study-act cycles, to ensure the participation and implementation of results by actors of the two levels of care.Key findings: Activities and outputs of the 4-year PAR are presented tough the research is still running.The first step of the research highlighted the interest that representatives of professionals (GP and hospital specialists) have for coordination between levels of care. It also revealed a lack of awareness regarding the role of respective work organizations and the difficulties to act as representatives.A coordination platform between one hospital and local GP organizations was developed with technical and organizational support of researchers. Regular meetings of representatives were organized, without financial incentive or policy constraint.The first and main activities were oriented toward explanations of the specific tasks and competencies of each levels of care. Practical improvements concerning coordination mechanisms were recorded such as transfer of information between levels of care, direct contacts between GP and specialists and definition of each other’s scope of action in routines for complex situations.Improved integration between organizations also improved ...