Perception of discomfort in dying patients is a risk factor for distress and bereavement among relatives. This study determined the perception of discomfort, the frequency of observed behaviors, and their association among relatives and among nurses who care for unresponsive dying patients. Sixty unresponsive dying patients' relatives and their nurses were asked to evaluate patient discomfort levels, the frequencies of six observed behaviors, and the suspected reasons for the patient discomfort. The mean levels of perceived discomfort were similar, but the association was poor between the relatives and the nurses. Relatives reported significantly more observed behaviors and associated more pain as a reason for patient discomfort than did nurses. The findings suggest that relatives are intensely attuned to their loved ones' conditions and reactions, and nurses' responses are fairly similar. Further research is warranted, however, to distinguish between the distress that the relatives perceive and the actual suffering of patients. (C) 2003 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.