Background: Compassion fatigue and professional quality of life are important in health and professional ethics. Aim: This study aimed to determine the relationship between compassion satisfaction, compassion fatigue, secondary traumatic stress, and moral injury in nurses. Research design: This research is a cross-sectional descriptive-analytical study. The research community of this research was all the nurses of the teaching hospitals of Ardabil city. Three questionnaires on demographic characteristics, the Professional Quality of Life Scale (ProQOL), and the Moral Injury Events Scale were (...) used to collect data. SPSS (version 22) software was used for data analysis. Participants and research context: The study recruited 297 nurses randomly selected from five teaching hospitals in Ardabil city. Ethical considerations: Ethical approval was obtained from the Ardabil University of Medical Sciences ethics committee (with the code of ethics IR.ARUMS.REC.1401.198). Informed consent was obtained from the participants. Results: The results showed that the mean compassion satisfaction score of this study’s participants was 37.61 ± 8.86, the mean compassion fatigue score of this study’s participants was 28.73 ± 7.04, and the mean secondary traumatic stress score of this study’s participants was 29.95 ± 7.84. The mean score of moral injury among nurses was 31.19 ± 8.54. The results showed a negative significant relationship between compassion satisfaction and moral injury ( p < 0.001). Also, there is a positive significant relationship between compassion fatigue and secondary traumatic stress with moral injury ( p < 0.001). Conclusion: The results of this study show a negative relationship between compassion satisfaction and moral injury. According to the results of the present study, nurse managers should implement educational interventions, create ethical processes, and clear ethical guidelines to reduce moral injury and increase compassion satisfaction. (shrink)