Objective: Analyze the perception of intensive care nurses regarding the limitation of therapeutic efforts (LET). Method: A 2-month cross-sectional, descriptive study carried out among Intensive Care nursing staff of our Hospital. An anonymous survey was used to assess the attitudes of intensive care nurses on LET. Results: Fifty-two nurses (86.6%), 57.7% women, with a working experience of 8.8 +/- 4.8 years and 17.7%, had some additional training in ethics. The decision not to hospitalize a patient whose short term quality of life is very poor changes when the patient's opinion is considered (36.5% vs 61.5%, p=0.008), a difference that is greater in male nurses without prior training in ethics. A total of 23.1% were not aware of the existence of agreed on guidelines on LET in the Service. A total of 17.3% consider that limiting treatment, either by not providing it or by withdrawing it, is a form of passive euthanasia, which would be an acceptable practice as opposed to euthanasia and 84.6% consider that administering a treatment is not the same as withdrawing it. Of those surveyed, 36.5% felt that the neither the nursing staff should not participate in the decision to limit treatment nor the patients (34.6%) nor family (23.1%). Conclusions: Nursing is not aware of the importance it can have, along with the family and patient, in decision making in relationship to the limitation of the treatment of the critical patient, providing a humanizing and ethical view of the care. (C) 2010 Elsevier Espana, S.L. and SEEIUC. All rights reserved.