Objective To evaluate the attitudes of critical care professionals concerning forgoing life-sustaining treatments in critically ill patients. Design and Setting Questionnaires (n = 1148) were distributed to all registrants at the annual Society of Critical Care Medicine meeting, and 600 (52%) were returned and analyzed. Patients None. Interventions None. Measurements and Main Results When confronted with an actual patient whose condition was deemed to be irreversible and terminal, 334 (56%) of 600 respondents were not disturbed by withholding or withdrawing treatment, whereas 156 (26%) of 600 respondents were more disturbed by withdrawing than withholding treatment. Five hundred thirty-six (89%) respondents had withheld and 519 (87%) had withdrawn life-prolonging treatments. Forgoing treatments was more common for academic physicians (329/343, 96%) and professionals responsible for the decision to forgo treatments (389/404,96%). Respondents believed the physician's professional duty to his or her patient was to preserve life foremost, but evaluate quality of life (342, 57%) or ensure quality of life foremost, but evaluate preservation of life (188, 31%). Conclusions Critical care professionals evaluate both the preservation of life and quality of life in their patients. Despite some discomfort in forgoing treatment, the majority of critical care professionals decide to forgo treatment in irreversibly, terminally ill patients.