The aim of this article is to describe the synthesis of the concept of moral stress and to attempt to identify its preconditions. Qualitative data from two independent studies on professional issues in nursing were analysed from a hypothetical-deductive approach. The findings indicate that moral stress is independent of context-given specific preconditions: (1) nurses are morally sensitive to the patient's vulnerability; (2) nurses experience external factors preventing them from doing what is best for the patient; and (3) nurses feel that they have no control over the specific situation. The findings from this analysis are supported by recent research on stress in the workplace but differ that the imperatives directing work are moral in nature. Stress researchers have found that persons who experience that they have no control over their work situation and at the same time experience high demands may be prone to cardiovascular diseases. An important question raised by this study is whether moral stress should be recognized as a health risk in nursing. Further research is required in order to generate intervention models to prevent or deal with moral stress.