BackgroundAlthough nurses are crucial to ensure patients’ peaceful death in hospitals, many nurses experience various ethical conflicts during end-of-life care. Therefore, research on nurses’ entire ethical decision-making process is required to improve nurses’ ethical decision-making in end-of-life care. This study aimed to identify Korean nurses’ ethical decision-making process based on their moral sensitivity to end-of-life patients.MethodsIn total, 171 nurses caring for terminal patients responded to the survey questionnaire. To measure the participants’ moral sensitivity and ethical decision-making process, we used the Korean version of the Moral Sensitivity Questionnaire and Nurses’ Ethical Decision-Making around End of Life Care Scale. Finally, multiple linear regression analysis was used to investigate the effect of moral sensitivity on nurses’ ethical decision-making.ResultsThe mean of moral sensitivity was 4.8 ± 0.5 (out of 7), and that of ethical decision-making was 4.6 ± 0.5 (out of 6). Among the sub-dimensions of ethical decision-making, the highest score was in perceived professional accountability (5.2 ± 0.5), and the lowest in moral reasoning and moral agency (3.9 ± 0.6); the score of moral practice was 4.4 ± 0.7. In the multiple linear regression model, moral sensitivity (β = 0.852, p < .001), clinical department (β = − 7.018, p = .035), ethics education (β = 20.450, p < .001), job satisfaction (β = 5.273, p < .001), and ethical conflict (β = − 2.260, p = 0.031) were influential ethical decision-making factors.ConclusionsThis study revealed a gap between nurses’ thoughts and practices through the ethical decision-making process. They failed to lead their thought to moral practice. It also implies that moral sensitivity could positively affect nurses’ ethical decision-making. To make nurses morally sensitive, exposing them to various clinical cases would be helpful. Additionally, ethics education and clinical ethics supporting services are valuable for improving nurses’ ethical decision-making. If nurses improved their ethical decision-making regarding end-of-life care, their patients could experience a better quality of death.