During the past decades, the establishment of external shopping centers have been increasing, causing debates on how they affect the viability and vitality of city centers. Instead of studying them as individual actors that are in competition with each other, it is interesting to examine them as components that together make cities complete trading destinations.  The purpose of this thesis is to study the coexistence and collaboration between different retail agglomerations. Retail agglomeration attributes are implemented to distinguish existing strengths and weaknesses for each trading venue, in order to identify where they complement each other. The research method is qualitative with an abductive approach. Six semi-structured interviews were conducted with respondents who represent different associations.  The findings of the research revealed that city centers and external shopping establishments are able to coexist if they complement each other through their individual offerings and experiences. Different retail agglomerations attract contrasting customer groups, allowing them to coexist. Collaboration between retail agglomerations can be implemented in several ways and can enhance the attractiveness of cities as trading destinations. The collaboration can occur by implementing shared marketing, shuttle bus services or collective events.  This research is limited to only investigating one medium sized city and three retail agglomeration formats. Furthermore, the choice of participants did not include consumers and store owners, which could have provided additional perspectives. The findings contribute to the study field by highlighting how retail agglomerations can coexist and collaborate and can be useful for other medium sized cities.