Advance care planning (ACP) and the subsequent advance directive document (ADD), previously known as "living wills", have not been widely used in Spain. The Ethics Group from the Spanish Society of Nephrology has developed a survey in order to investigate the opinion of dialysis patients regarding the ADD and end-of-life care. Patients received documentation explaining ACP and filled out a survey about their familiarity with and approval of the ADD. Seven hospital dialysis centres participated in the study for a total of 416 active dialysis patients. Questionnaires were distributed to 263 patients, 154 of which answered (69.2% completed them without assistance). The rates for ADD implementation (7.9%) and designation of a representative person (6.6%) were very low. Most of the patients clearly expressed their wishes about irreversible coma, vegetative state, dementia and untreatable disease. More than 65% did not want mechanical ventilation, chronic dialysis, tube feeding or resuscitation if cardiorespiratory arrest occurred. They reported that an ADD could be done before starting dialysis but most thought that it should be offered only to those who requested it (65% vs 34%). In conclusion, patients have clear wishes about end-of-life care, although these desires had not been documented due to the very low implementation of the ADD.