question: OBJECTIVES: ICU professionals are at risk of developing burnout due to coronavirus disease 2019. This study assesses the prevalence and incidence of burnout symptoms and moral distress in ICU professionals before and during the coronavirus disease 2019 crisis. DESIGN: This is a longitudinal open cohort study. SETTING: Five ICUs based in a single university medical center plus another adult ICU based on a separate teaching hospital in the Netherlands. SUBJECTS: All ICU professionals were sent a baseline survey in October-December 2019 (252 respondents, response rate: 53%), and a follow-up survey was sent in May-June 2020 (233 respondents, response rate: 50%). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Burnout symptoms and moral distress measured with the Maslach Burnout Inventory and the Moral Distress Scale, respectively. The prevalence of burnout symptoms was 23.0% before coronavirus disease 2019 and 36.1% at postpeak time, with higher rates in nurses (38.0%) than in physicians (28.6%). Reversely, the incidence rate of new burnout cases among physicians was higher (26.7%) than nurses (21.9%). Higher prevalence of burnout symptoms was observed in the postpeak coronavirus disease 2019 period (odds ratio, 1.83; 95% CI, 1.32-2.53), for nurses (odds ratio, 1.77; 95% CI, 1.03-3.04), for professionals working overtime (odds ratio 2.11; 95% CI, 1.48-3.02), and for professionals directly engaged with care for coronavirus disease 2019 patients (odds ratio, 1.87; 95% CI, 1.35-2.60). Physicians were more likely than nurses to develop burnout symptoms due to coronavirus disease 2019 (odds ratio, 3.56; 95% CI, 1.06-12.21). CONCLUSIONS: This study shows that overburdening of ICU professionals during an extended period of time leads to symptoms of burnout. Working long hours and under conditions of scarcity of staff, time, and resources comes at the price of ICU professionals' mental health.