Summary Certain activity sectors are particularly affected by problems that impact their workers’ health and safety. One example is the Youth Centre sector, where the work is generally characterized by high emotional demands due to frequent contacts with children and families in crisis and to a lack of the resources needed to effectively respond to these emotional demands. Moreover, there is growing recognition of the potential impacts of emotionally demanding work on both physical and psychological health (post-traumatic stress, musculoskeletal disorders, psychological distress, absenteeism, high staff turnover, etc.), impacts that not only affect workers, but also the organizations that employ them. However, while the importance of developing organizational interventions to prevent the potential impacts of exposure to emotionally demanding work is well documented, little is known specifically about the interventions that should be implemented to mitigate the impacts of this type of work. The main objective of this study was to implement and assess an employer/employee preventive intervention designed to mitigate the potential impacts of emotionally demanding work on workers in youth centres. More specifically, the researchers’ aim was to (1) identify the psychosocial stressors (risk factors) and protective factors present in the target organization; (2) develop appropriate interventions for both reducing the psychosocial stressors in the workplace and optimizing the existing protective factors; (3) assess the intervention implementation process; and (4) measure the intervention’s effects. The study population consisted of workers in a youth centre and the first-level managers who supervise the teams working in close contact with clients. The study was conducted in three phases: (a) the development phase, during which a profile of the situation was developed and concrete intervention goals were identified, (b) the implementation phase, during which the actual interventions were identified and implemented, and (c) the assessment phase, during which the intervention process and its effects were evaluated. Quantitative and qualitative research methods were used to carry out the three phases. Specific interventions were developed by the Intervention Support Group (ISG), an employer/employee group created during the process. With respect to the study’s findings, first, the project provided an exhaustive profile of the risk and protective factors present in the workers and their supervisors. Based on these factors, the ISG members prioritized the interventions that emerged from their reflections. The majority of these interventions focused on improving support resources, which was consistent with the resource needs identified during the initial research phase. The intervention process as a whole and its effects were also analyzed. Among the findings that emerged from this analysis, one element – which pertained to the context, not to the actual project – was pervasive: the reform of health and social services that took place during the same period as the project. This major overhaul completely destabilized the establishment hosting the research team, and consequently, several of the foundations of the project itself. However, thanks to the strong partnership already in place and the joint employer/employee nature of the project, the intervention process saw the light of day, and (incidentally) had effects that could be studied. The main winning conditions, already in place when the intervention process began, also emerged from the analysis. Based on the testimonials, these conditions helped keep the research-intervention process going with assistance from the Intervention Support Group (ISG). An assessment was also drawn up of the challenges encountered, as was an overview of a set of factors that promoted or hindered the success of the process. All these findings could eventually serve as a basis for reflection for any organization wishing to undertake a preventive intervention process. In addition to the projects developed by the ISG, such as obtaining a room for employees or access to a specialized resource person from the Employee Assistance Program, or developing a program for peer helpers, the research team was able to observe that the overall research-intervention process, begun in 2012, appeared to have a particularly beneficial effect on the workplace. This beneficial effect was attributable to the fact that all the workplace actors (workers, unions, supervisors and senior management) formally recognized that the workers – and their supervisors – were exposed to an emotionally demanding work environment, and accordingly, had a shared desire to take preventive action. The originality of this study lies in its participatory, workplace intervention process that was built on rigorous theoretical and methodological foundations and also underwent systematic evaluation using a recognized evaluation model. While the study was conducted in a youth centre, the theoretical knowledge and practices developed may be useful in other workplaces affected by emotionally demanding work, such as long-term residential care facilities (CHSLDs), hospitals, emergency services or the sector working with people who have intellectual or physical impairments.