Background: Most studies on euthanasia fail to explain the intentions of health professionals when faced with performing euthanasia and are atheoretical. Research objective: The purpose of this study was to identify the psychosocial determinants of nurses’ intention to practise euthanasia in palliative care if it were legalised. Research design: A cross-sectional study using a validated anonymous questionnaire based on an extended version of the Theory of Planned Behaviour. Participants and research context: A random sample of 445 nurses from the province (...) of Quebec, Canada, was selected for participation in the study. Ethical considerations: The study was reviewed and approved by the Ethics Committee of the Centre hospitalier universitaire de Québec. Findings: The response rate was 44.2% and the mean score for intention was 4.61 ± 1.90 (range: 1–7). The determinants of intention were the subjective (odds ratio = 3.08; 95% confidence interval: 1.50–6.35) and moral (odds ratio = 2.95; 95% confidence interval: 1.58–5.49) norms. Specific beliefs which could discriminate nurses according to their level of intention were identified. Discussion: Overall, nurses have a slightly positive intention to practise euthanasia. Their family approval seems particularly important and also the approval of their medical colleagues. Nurses’ moral norm was related to beneficence, an ethical principle. Conclusion: To our knowledge, this is the first study to identify nurses’ motivations to practise euthanasia in palliative care using a validated psychosocial theory. It also has the distinction of identifying the ethical principles underlying nurses’ moral norm and intention. (shrink)