Most patients diagnosed with a life threatening illness want to know the truth regarding their situation to enable them to plan their remaining time their family's future (Fallowfield 2002). In palliative care practice dilemmas and conflicts about truth-telling may involve collusion between health care professionals and the patients' relatives to withhold the truth from the patient. This article discusses the ethical theory and legal considerations pertaining to truth-telling and collusion in the UK. It focuses on situations where the adult patient is deemed to be competent and extends arguments about collusion beyond ethical theoretical perspectives and legal considerations to include the emotional and practical consequences of withholding the truth. A case study serves to highlight the complex interplay between these aspects and the author argues that they must all be taken into account when making decisions about truth-telling. The potential role of the nurse within the context of truth-telling and the avoidance of the pitfalls of collusion are considered.