Background: Moral distress is a complex phenomenon frequently experienced by critical care nurses. Ethical conflicts in this practice area are related to technological advancement, high intensity work environments, and end-of-life decisions. Objectives: An exploration of contemporary moral distress literature was undertaken to determine measurement, contributing factors, impact, and interventions. Review Methods: This state of the science review focused on moral distress research in critical care nursing from 2009 to 2015, and included 12 qualitative, 24 quantitative, and 6 mixed methods studies. (...) Results: Synthesis of the scientific literature revealed inconsistencies in measurement, conflicting findings of moral distress and nurse demographics, problems with the professional practice environment, difficulties with communication during end-of-life decisions, compromised nursing care as a consequence of moral distress, and few effective interventions. Conclusion: Providing compassionate care is a professional nursing value and an inability to meet this goal due to moral distress may have devastating effects on care quality. Further study of patient and family outcomes related to nurse moral distress is recommended. (shrink)