Purpose : The development of organizational collectives is a lever for innovation to meet the major challenges of technological, social and environmental change. The aim of this research is to characterize the process by which organizational collectives. Design/methodology/approach : This is a case study of six private healthcare establishments mobilized around an organizational project. A seven-month research-intervention was carried out with six healthcare establishments mobilized around an organizational human resources (HR) project. The transformative aim was to encourage the emergence of an organizational collective by playing a functionalist role in the project methodology while also reflecting on the organizational practices observed. Using an abductive and constructivist approach, the study material revolved around the mental representations of the practitioners involved in this collective, gathered through semi-structured interviews, participant observations and documentary research. Findings : This research characterizes a process of emergence of a collective of organizations that includes an activation phase consisting of triggering factors contributing to the construction of shared mental representations and a phase of specific structuring of the collective action of the organization collective in the making. These two phases lay the foundations for the organizational collective responsible for managing not only the initial project but also other projects and operations, thus ensuring its longevity. Research limitations/implications : It is based on a single exploratory case study with a limited sample of members of an organizational collective. In addition, it is specific to the healthcare sector, the HR field and the hierarchical level of the members we worked with. With a view to verifying, consolidating and generalizing knowledge, it would be pertinent to test these results in other empirical contexts. Practical implications : The direct managerial interest of our study will therefore lie in the recommendations addressed to players wishing to become involved in a collective of organizations. The organizational collective is founded on a durability that goes beyond the temporary framework of the project. It would be interesting to know how to contribute to the durability of this collective from the outset, in particular through the “routinization” of organizational practices generated within the framework of this regulation by management systems. This collective of organizations also generates a value system which, if we refer to the results of our research, goes beyond the objectives of solving the project’s problem. It would also be timely to pursue research into the value creation of a collective of organizations. Social implications : For a number of years, healthcare policies have been encouraging the development of collective organizations through greater coordination, supply chains, care networks, etc. (Valette, 2019). Nonetheless, we have to acknowledge the scarcity of management science research on the subject in this sector, despite the fact that public policy incentives to reorganize the healthcare system are constantly highlighting them. In concrete terms, since the 2016 Modernization Act, numerous organizational collectives in response to major public health challenges have been deployed, such as professional communities in healthcare territories, “Art 51” pathways, etc. (Observatoire National de la Qualité de vie au travail, 2021). Originality/value : Despite extensive research into the characteristics and modes of operation of organizational collectives, little is known about their emergence process (Viollet and Dreveton, 2023). Moreover, there is little management science research on organizational collectives in the healthcare sector, even though public policy incentives are constantly encouraging them. Our aim is to fill this gap by answering the question: How does an organizational collective emerge?