In a Swedish nation-wide study, 1196 members of the general public, and 121 physicians and 339 nurses drawn from 29 intensive care units were questioned about the use of ventilator treatment for severely ill patients. Response rates were 64%, 88% and 86%, respectively. Two typical case history scenarios were presented: one describing a conscious and competent patient with pneumonia and severe cancer, and the other describing a patient who had been comatose for 1 month following head trauma. In the case of the cancer patient, 49% of the general public, 63% of the physicians and 59% of the nurses answered that theywould wish that the ventilator treatment be discontinued, if they were the patient. In the case of the comatose patient, 48% of the general public, 82% of the physicians and 70% of the nurses answered that they would wish that the ventilator treatment to be discontinued, if they were a relative of the patient. Respondents own preferences, in the three groups,for life support favoured withdrawal of ventilator treatment.