Introduction: Occupational stress has negative effects on employee's health and organizational productivity. Nurses in emergency department are more exposed to stress than nurses in other departments. Aim: To explore nurses' experiences of occupational stress in emergency departments in private hospitals in Bangkok, Thailand. Design: A descriptive qualitative design, with a deductive approach based on the Job Demand-Control-Support model was used. Methods: Fifteen emergency department nurses at two different hospitals were interviewed and the data were analyzed using a manifest content analysis. Results: Three main categories: "work context is an issue", "consequences of reactions to stress", and "coping with work stress", including seven sub-categories emerged from the data analysis. Conclusion: The patients' and their relatives' behaviors were experienced as the primary stressor at the private hospital, in addition to excessive work tasks. Other important stressors were misunderstanding and conflicts between emergency department nurses and the other health care professionals, presumably related to hierarchy and power relations between health care professions. Creating a better working environment and a balance between the number of patients and nurses would reduce workload and stress, encourage ED nurses to stay in the profession and ultimately maintain patient safety.