Aims: Paper I: To examine the prevalence of posttraumatic stress reactions among ambulance personnel and to investigate whether different levels of Sense Of Coherence are related to different consequences of traumatic stress.Paper II: To uncover the essence of traumatic events experienced by Swedish ambulance personnel. Paper III: To investigate the association between daily work exposure to traumatic events and emotional and mental wellbeing, and if self knowledge influence how well you handle the effects of daily work exposure to such events.Paper IV: To uncover and deepen the understanding of the way ambulance staff experience and handle traumatic events, and to develop the understanding of the life world of the participants.Methods: Paper I & III: To estimate the prevalence of trauma related disorders (Paper I), a representative group of 362 ambulance personal was surveyed through use of Antonovsky s 13-item version of SOC-13 Scale. To measure reactions to traumatic events two instruments were used, Impact of Event Scale (IES-15) and the Post Traumatic Symptom Scale (PTSS-10). A correlate was established between posttraumatic symptoms using IES-15 and the Professional Self Description Form (Paper III).Paper II & IV In the study (Paper II) written stories from 52 ambulance personnel describing an experienced traumatic event were analysed by the van Kaam method. In the study ten ambulance personnel were interviewed. To reach a deeper understanding an interpretative Heideggerian approach was applied, based on an existential perspective (Paper IV).Results: Paper I & III: A total of 223 of the ambulance personnel reported that they had had experience of what they described as traumatic situations. Of those who reported a traumatic situation 15.2% scored 31 or more on the IES-15 sub scale. On the PTSS-10 sub scale 12.1% scored 5 or more, which indicates a relatively strong reaction. The study indicates that lower sense of coherence predicts post-traumatic stress. Other predictors for the extent of traumatic stress were longer job experience, age, physical and psychological workload (Paper I). There were significant differences on PSDF sub scales between those with or without posttraumatic symptoms (Paper III). Paper II & IV: Findings indicate that the ambulance personnel have a strong identification with the victims and it is impossible to prepare for events that are unforeseen and meaningless. To handle the overwhelming feelings of identification, the personnel have to gain understanding through talking about those feelings (Paper II). The findings show that post-traumatic stress symptoms, guilt, shame and self-reproach are common after duty related traumatic events (Paper IV).Conclusions: The mental health and emotional well being of ambulance personnel appears to be at risk in accident and emergency work. The high prevalence of PTSD symptoms in ambulance personnel indicates a normal inability to cope with posttraumatic stress caused by their daily work.