AimsTo describe assistant nurses' experiences of thirst and ethical challenges in relation to thirst in terminally ill patients in specialized palliative care (PC) units.DesignA qualitative, reflexive thematic design with an inductive analysis was used.MethodsData were collected during November 2021-January 2023. Twelve qualitative interviews with assistant nurses working in five different specialized PC units in different hospitals in Sweden were conducted. The interviews were transcribed verbatim and analysed with a reflexive thematic analysis. The study was guided by the Standards for Reporting Qualitative Research (SRQR).ResultsTwo main themes were found in this study. (1) 'A world of practice for thirst relief' where assistant nurses present a task-oriented world where the knowledge of thirst is an experience-based unspoken knowledge where mainly routines rule. (2) Ethical challenges presents different ethical problems that they meet in their practice, such as when patients express thirst towards the end of their life but are too severely ill to drink or when they watch lack of knowledge in the area among other health professionals.ConclusionThirst in dying patients is a neglected area that assistant nurses work with, without communicating it. Their knowledge of thirst and thirst relief are not expressed, seldom discussed, there are no policy documents nor is thirst documented in the patient's record. There is a need for nurses to take the lead in changing nursing practice regarding thirst.Patient or Public ContributionNo patient or public contribution.ImpactIn palliative care, previous studies have shown that dying patients might be thirsty. Assistant nurses recognize thirst in dying patients, but thirst is not discussed in the team. Nurses must consider the patient's fundamental care needs and address thirst, for example in the nursing process to ensure patients quality of life in the last days of life.Reporting MethodThe study was guided by the SRQR.What does this Article Contribute to the Wider Global Clinical Community?Thirst is a distressing symptom for all humans. However, when a patient is dying, he or she loses several functions and can no longer drink independently. The knowledge from this article contributes to our understanding of current practice and shows an area that requires immediate attention for the improvement of fundamental palliative care delivery.