Summary In Quebec, people 45 and over represent an increasing proportion of the workforce in the health care and social services sector. To ensure the required balance between the growing demand for health care services and the supply of labour in this context of sociodemographic change, health care organizations are having to address the challenge of optimizing the participation of older workers. That requires them not only to ensure efficient management of incapacitating workplace situations among workers 45 and older, but also to try to prevent this type of injury and help those who have suffered such injuries to remain at or return to work. This study had three main objectives: Map out the return-to-work trajectories of workers 45 and older who have suffered an occupational injury, in the health and social services sector, taking into account possible sex-related differences. Examine the factors associated with the various trajectories. Map out rehabilitation practices for older workers and identify those that facilitate or hinder the return to work of older workers who have suffered an occupational injury. Combining a longitudinal approach and a mixed method research design, the study is organized into two parts: A quantitative part: return-to-work trajectories of workers 45 and over and analysis of the associated factors (objectives 1, 2). The design was for a longitudinal prospective study of a cohort of workers 45 and over in health care and social services. Two data gathering techniques were used: a questionnaire administered three times and the collection of administrative data (hours worked). The modelling was based on latent class growth analysis. A qualitative part: mapping out of organizational practices in occupational rehabilitation (objective 3). The design was a multiple case study (3 cases) with nested analysis levels. The main sources of data were interviews and the related documentation. Findings: Quantitative part. The classification step resulted in four trajectories that respondents 45 and older follow after a workplace injury: (1) progressive reduction in hours worked; (2) slow, progressive return to work; (3) immediate return to normal situation; and (4) quick, progressive return to work. For the last two trajectories, which represent three quarters of respondents, injured workers go back to working the same number of hours they worked before the injury, either immediately upon returning to work, or gradually over the course of the six two-week periods that follow the return to work. For the first two trajectories, however, which account for the remaining one quarter of respondents, when the injured workers completed their sixth period after return to work, they were still far from the number of hours worked before their injury, and one of the two trajectories even showed a downward curve. Multivariate analyses highlighted just two main factors associated with the more unfavourable trajectories: higher psychological demands of the job and a longer period of absence. Accidents that resulted in long periods of absence (average of 94 days) affected two job categories in particular: nursing and cardiorespiratory care jobs and paratechnical jobs. With regard to sex, the findings show that accidents leading to a long period of absence affect women in particular (75.7%), which reflects the fact they account for a higher proportion of employees in the job categories in question. The findings also show a significantly higher average length of absence among women (104 days) than among men (67 days). As regards the two age groups targeted in this study, greater vulnerability was seen among 45-to-55-year-olds than among those age 56 and over, with a longer period of absence following an accident and a higher rate of intention to leave their profession. Qualitative part. The analyses led to three main takeaways: Organizational systems and procedures that have not yet reached their full maturity, with the following consequences: sometimes incomplete monitoring of occupational health and safety (OHS) problems, event analysis procedures that do not go deep enough, inadequate communication and a lack of coordination. Limited commitment of some organizational stakeholders to solving OHS problems, with the following consequences: a commitment shown at the senior levels of an organization that doesn’t always filter down to the lower levels, OHS teams confined to administrative roles and low employee awareness of the potential risks of their work environment. Shortcomings involving both the extent and the depth of organizational initiatives: a vision that doesn’t take in the full spectrum of initiatives, and more attention given to actions focused on individuals rather than to measures aimed at changing the work environment. The study suggests five ways for organizations to optimize their occupational injury monitoring, prevention and management systems for older workers: (1) Pay particular attention to two especially vulnerable subgroups; (2) Focus on work organization as a change lever; (3) Invest in mechanisms aimed at ensuring the commitment of all organizational stakeholders; (4) Strengthen the organizational systems for preventing and managing occupational injury situations; and (5) Focus on actions that simultaneously target workers and their work environment. Implications for research. In terms of research, this study underscores the urgency of finding empirically validated ways to optimize the attendance at work and the work trajectories of workers 45 and over, especially for workers in the most vulnerable job categories. Contrary to current methods, the findings suggest focusing on multidimensional initiatives that are operationalized at the individual and organizational levels, based on the needs of stakeholders and developed in tandem with them. Other qualitative, longitudinal studies of workers who have suffered an occupational injury are also needed to provide more extensive data on what they experience and a better understanding of the mechanisms whereby actions and processes in various spheres (institutional, organizational and individual) affect their trajectories and attendance at work.