Introduction: There are many factors to be identified and flows to be established in the interface between primary care and the emergency care network. Comparing different health systems with processes of health policies based on regionalization can result in new health planning instruments. In this sense, understanding the regional arrangements and dynamics of the Canadian health system in a comparative study with the Brazilian reality enabled the implementation of strategies for the development of innovations and health management planning in Brazil. Objective: To identify the factors that interfere in the establishment of primary care and emergency care network interfaces in different socio-spatial realities (regions) and in different health systems. Methods: Two case studies: in Brazil, using mixed methods and in Canada, qualitative methods. The study in the North-Barretos and South-Barretos regions (São Paulo, Brazil) consists of interviews with key informants and analysis of secondary data. In the Mississauga