Background: Ambulance nurses display stress symptoms, resulting from their work with patients in an emergency service. Certain individuals seem, however, to handle longstanding stress better than others and remain in exposed occupations such as ambulance services for many years. This paper examines stress inducing and stress defusing factors among ambulance nurses. Methods: A qualitative descriptive design using critical incident technique was used. A total of 123 critical incidents were identified, and a total of 61 strategies dealing with stress were confirmed. In all, 13 sub-categories (seven stress factors and five stress reducing factors) were merged into four categories (two stress categories and two stress reducing categories). Results and conclusion: The study shows that ambulance nurses in general experience emergency calls as being stressful. Unclear circumstances increase the stress level, with cases involving children and childbirth being especially stressful. Accurate information and assistance from the dispatch centre reduced the stress. Having discussions with colleagues directly after the assignment were particularly stress reducing. Advanced team collaboration with teammates was viewed as effective means to decrease stress, in addition to simple rituals to defuse stress such as taking short breaks during the workday. The study confirmed earlier studies that suggest the benefits of defusing immediately after stress reactions. (C) 2016 Elsevier Ltd. All rights reserved.