Some people frequently use hospital services because of more complex health needs resulting from factors such as multiple chronic diseases, mental health disorders and psychosocial difficulties, or a combination of these factors. These frequent users are at greater risk of experiencing difficulties in using health care and are at greater risk of disability and mortality. This research project aims to develop and evaluate the role of a system navigator in four family medicine groups (FMGs) of the Saguenay-Lac- Saint-Jean region, played by one or more nurses to co-ordinate the care of frequent users of services in co-operation with the hospital centre’s case manager. The knowledge generated by this project will be used to inform managers’ and management’s decision-making and thus improve care. This new role nurse will make it possible to improve the care experience and health status of these patients while improving the performance of the healthcare system.