This article seeks to shed light on the beliefs that influence nurses' intention of respecting or not respecting an advance directive document, namely a living will or a durable power of attorney. Nurses' beliefs were measured using a 44-statement questionnaire. The sample was made up of 306 nurses working either in a long-term care centre or in a hospital centre offering general and specialized care in the province of Qu?bec. The results indicate that nurses have a strong intention of complying with advance directives written by patients. The analysis also shows that four variables determine the strength of this intention: respect for autonomy; the location of the workplace; justice; and the dimension of relationships and emotions. Although these documents favour the expression of patients' wishes, nurses should be aware that they do not systematically guarantee respect of a patient's autonomy, nor do they replace a relationship based on trust between patients and health care professionals.