Study Objective: The present study is aimed at providing an assessment of the changes in burnout, job strain, isostrain, sleepiness, and fatigue levels over time and identifying factors associated with these symptoms among healthcare workers in French emergency departments (EDs). Method: We conducted a prospective, multicenter study in four EDs and an emergency medical service. Participants completed questionnaires at inclusion and at 90 days to assess burnout, job strain, isostrain, sleepiness, and fatigue. Results : A total of 211 respondents (43.5%) completed the questionnaires at inclusion. At the beginning of the study, 84 (40.8%) participants presented symptoms of burnout, 86 (43.2%) had symptoms of job strain, and 58 (29.4%) of isostrain. Forty‐two (20.1%) healthcare workers presented symptoms of sleepiness, and 8 (3.8%) had symptoms of fatigue. We found that symptoms of burnout were more frequent for healthcare workers with a previous psychiatric history (55.3% vs. 39.1%, p = 0.02) and were lower among participants who had at least one dependent child (33.1% vs. 48.3%, p = 0.013). Symptoms of job strain were higher among administrative staff compared to physicians (55.6% vs. 28.7%, p = 0.01) and among healthcare workers with managerial responsibilities compared to those without (45.6% vs. 28.8%, p = 0.015). Symptoms of isostrain were higher among administrative staff (42.3%) compared to paramedics (34.1%) and physicians (19.8%, p = 0.026). Conclusion: We identified that potential factors associated with the emergence of symptoms of burnout and job strain are suggested, underlining several areas of improvement for the prevention against mental health disorders in the specific population of ED healthcare workers. Trial Registration: ClinicalTrials.gov identifier: NCT04383886 .