Nurses in an intensive care unit (ICU) often play key roles to improve the quality of end-of-life care. During those times, many nurses report they feel ambivalent in the caring between life and death. The purpose of this study was to analyze the concept of ambivalence that ICU nurses often experienced in end-of-life care. As a method, this study was conducted with the concept analysis using the hybrid model Schwartz-Barcott and Kim (1986) presented, naming the complex and dual feelings nurses experience during end-of-life care in ICU as ambivalence. In the theoretical phase and from the literature review, characteristics of ambivalence were identified. During the fieldwork phase, in-depth interviews were conducted with five nurses. In the final phases, a theoretical description was extracted of ambivalence in ICU nurses during end-of-life care. In terms of results, external factors (i.e., realistic context, contradictions in nursing activities themselves) and internal factors (i.e., personal tendencies, conflicting perceptions of dying, occupational awareness of nurses, role conflicts) were derived as antecedents of ICU nurses’ ambivalence during end-of-life care. Attributes were divided into intrinsic and existential dimensions. Intrinsic dimensions resulted in "coexistence of opposing equivalent values," "uncertainty," "hiddenization," "value confrontation may occur sequentially," and "absence of willingness to resolve." In existential dimensions, the following conflicts were derived: "pressure on work versus sympathy about family grief," "helplessness due to failure of medical care versus sadness for patient death" and "role as a nurse versus sadness felt during end-of-life care.” The results are organized into negative assessments of oneself and adaptations to ambivalence. In conclusion, through this concept analysis, the hope is that ICU nurses will be able to prevent progressing to burnout by accurately and actively facing and managing their own feelings during end-of-life care. Furthermore, this research is expected to serve as the cornerstone of developing theories for clinicians who provide end-of-life care.