Study objective: We explored physicians' perceptions of and attitudes toward triage and end-of-life decisions for elderly critically ill patients at the emergency department (ED)–ICU interface. Methods: This was a qualitative study with thematic analysis of data collected through semistructured interviews (15 emergency physicians and 9 ICU physicians) and nonparticipant observations (324 hours, 8 units, in 2 hospitals in France). Results: Six themes emerged: (1) Physicians revealed a representation of elderly patients that comprised both negative and positive stereotypes, and expressed the concept of physiologic age. (2) These age-related factors influenced physicians' decisionmaking in resuscitate/not resuscitate situations. (3) Three main communication patterns framed the decisions: interdisciplinary decisions, decisions by 2 physicians on their own, and unilateral decisions by 1 physician; however, some physicians avoided decisions, facing uncertainty and conflicts. (4) Conflicts and communication gaps occurred at the ED- ICU interface and upstream of the ED-ICU interface. (5) End-of-life decisions were perceived as more complex in the ED, in the absence of family or of information about elderly patients' end-of-life preferences, and when there was conflict with relatives, time pressure, and a lack of training in end-of-life decisionmaking. (6) During decisionmaking, patients' safety and quality of care were potentially compromised by delayed or denied intensive care and lack of palliative care. Conclusion: These qualitative findings highlight the cognitive heuristics and biases, interphysician conflicts, and communication gaps influencing physicians' triage and end-of-life decisions for elderly critically ill patients at the ED-ICU interface and suggest strategies to improve these decisions. [Ann Emerg Med. 2016;68:28-39.]