Moral distress is described as the feeling resulting from the impediment to an action considered morally appropriate, mainly due to institutional obstacles such as the lack of resources and the high workload. Main consequences are physical symptoms, such as malaise, crying and sleep disorders and psychological symptoms, such as frustration, impotence and guilt, as well as organizational implications, mainly related to withdrawal and abandonment of employment. Considering that the work context may influence the experience of morally problematic situations, the objective of these study was to analyze the phenomenon of moral distress among nurses in Brazil and in Portugal. It is a methodological research for development, searching for evidence of validity and refinement of a research instrument. The research started with the analysis of 38 studies for the construction of a scale to identify risk factors for moral distress. The search for evidence of validity included an analysis of judges, for content validation, and an exploratory factorial analysis, for construct validation, with a sample of 268 Brazilian nurses and 278 Portuguese nurses. The result was a scale with evidence of validity, Cronbach's Alpha of 0,913 and 0,790, Kaiser-Meyer Olkin test of 0,869 and 0,914 and a significant Bartlett (p <0,001). About 59,8% of the variance was explained by 30 items, divided into seven factors in the Brazilian version, and about 53,9% of the variance was explained by 20 items, divided into four factors in the Portuguese version. The experience of risk factors for moral distress was considered moderate in Brazil and low in Portugal. The variables that showed a significant association with the highest risk for moral distress in both countries were the type of work context, the hours of work, being in moral distress and having the intention to leave the current job. Research in the field of moral distress can, among other things, help in identifying the challenges and difficulties that most concern nurses in their work context. In order to contribute to the development of coping strategies and to improve professional retention and satisfaction, researches about moral distress may positively reflect on the quality of care.