The Purpose of this study was to understand the meaning of experiences in Intensive Care Unit Nurses under ethical dilemma situation. Methods: Data was collected using in depth interviews and analyzed based on phenomenological method by Giorgi . The participants were six nurses who worked on the intensive care unit of University Hospital, Korea. Results: All participants experienced moral distress and conflict under ethical dilemma situation. 10 themes were identified. 1.That the encounter deaths. 2. Moral distress and burn out related to end of life care. 3.Administrate meaningless life sustaining therapies. 4.Moral conflict from withdraw all treatment due to DNR decision. 5.Determining brain death situation regarding organ transplantation. 6.Uncertainty about the best care for the patients and family. 7.Moral obligation to do best for all patients. 8.Allocation of scarce resources. 9.Dishonesty. 10.Ethical conflict from uncooperative relationship with doctor. Conclusion: Theses results revealed the importance of support system and education. The result is useful to develop Nursing Ethical Education Program and intervention program which can be expandable for intervention program for clinical nurses and nursing students.