Introduction: The COVID-19 pandemic has caused increasing levels of mental health problems such as anxiety and depression among doctors, nurses and other healthcare workers in hospitals or health centers. The main objective of this study was to assess the mental health, job stressors, and burnout among healthcare workers in Iran. Materials and Methods: A cross-sectional study was performed in the primary healthcare centers and hospitals affiliated with six of the medical universities in Iran. The selection of participants was done using multi-center convenient sampling. The Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Copenhagen Burnout Inventory were used for gathering data through an online platform. Data related to job stressors were obtained using a validated checklist. Data analysis was performed using Chi-square and multiple regression tests and the phi coefficient. Results: The results of our study showed that 53% of the healthcare workers of the hospitals