OBJECTIVES: The objectives of the present study were to examine the degree and the sources of mental distress and the coping strategies adopted by healthcare workers (HCW) of emergency departments (ED) in Hong Kong during the outbreak of severe acute respiratory syndrome (SARS). METHODS: Questionnaires were sent to all doctors, nurses and healthcare assistants (HCA) working in the ED of all public hospitals. The overall degree of mental distress was measured by a single-item 11-point Likert scale. The source of distress was measured by an 18-item questionnaire, which was designed based on the experience of clinical psychologist colleagues providing counselling to staff taking care of SARS patients. The Brief Cope questionnaire was used to study coping strategies adopted by staff. RESULTS: A total of 1260 questionnaires were sent out and the response rate was approximately 37%. The mean overall distress level was 6.19 out of a 10-point scale. The mean overall distress levels for doctors, nurses and HCA were 5.91, 6.52 and 5.44, respectively (F(2,420)=6.47, P<0.005). The overall distress level for nurses was significantly higher than for HCA (P<0.005) but not doctors. The overall distress level was highly and significantly correlated with the six sources of distress: vulnerability/loss of control (r=0.68); health of self (r=0.62); spread of virus (r=0.60); health of family and others (r=0.59); changes in work (r=0.46); being isolated (r=0.45). The scores for nurses were significantly higher than for doctors in terms of the six sources of distress (all P values <0.01). HCA were significantly higher than doctors (but not nurses) in worrying about their family's and others' health (P<0.05). In terms of coping strategies, doctors were significantly more likely than nurses and HCA to use planning (P<0.05 and <0.01 respectively); nurses were significantly more likely than doctors to use behavioural disengagement (P<0.01); whereas HCA were significantly more likely than doctors to use self distractions (P<0.05). CONCLUSIONS: SARS had caused a significant level of distress among ED staff. The distress level was highest for nurses, followed by doctors and HCA. The three most important variables that could account for the distress level were loss of control/vulnerability, fear for self-health and spread of the virus. Overall, the more frequently adopted coping strategies were acceptance, active coping, and positive framing.