Organ donation after brain death is an alternative to living organ donation, which has various risks and is a means of addressing organ supply shortages. In South Korea, primarily, the organ donation decision is made by the brain-dead donor's family under the guidance of medical staff. Intensive care unit nurses, who are consistently present with patients, can significantly influence families' decision-making process. Hence, nurses' experiences of caring for brain-dead donors should be explored to obtain detailed explanations of the related complex social phenomena. This qualitative study aimed to understand the structure and nature of nurses' experiences using Colaizzi's phenomenological method. Data were collected from 10 intensive care unit nurses from a hospital-based organ procurement organization between June 27 and September 10, 2022. Twelve themes and 5 components were identified from participants' interviews, including “nursing with regret,” “enduring agony from repeatedly caring for deceased organ donors,” “lack of a support system,” “deep emotional pain and scarring left after care,” and “balancing emotions.” It is necessary to clarify the required nursing interventions and role of nurses in intensive care units who care for brain-dead donors and develop specific guidelines to assist them in their work.