Abstract Background: The success of biotechnology has created moral and ethical dilemmas concerning end-of-life care in the Intensive Care Unit (ICU). Whilst the competent individual has the right to refuse or embrace treatment, ICU patients are rarely able to exercise this right. Thus, decision-making is left to medical professionals and family/significant others. Aim: This study aimed to explore the lived experience of ICU nurses caring for clients having treatment withdrawn or withheld, and increase awareness and understanding of this experience amongst other health professionals. Methods: Van Manens’ (1990) phenomenological framework formed the basis of this study as it provided an in-depth insight into the human experience. A convenience sample of ten ICU Nurses participated in the study. Conversations were transcribed verbatim and analysed using a process of thematic analysis. Results: Five major themes emerged during the analysis. These were: (1) comfort and care, (2) tension and conflict, (3) do no harm, (4) nurse–family relationships and (5) invisibility of grief and suffering. Conclusion: The experience of providing care for the adult having treatment withdrawn or withheld in the ICU represents a significant personal and professional struggle. Improvements in communication between health professionals, debriefing and education about the process of withdrawing or withholding treatment would be beneficial to both staff and families and has the potential to improve patient care and reduce burden on nurses.