Literature on assessment of symptom distress has focused primarily on patients' and nurses' perceptions in the hospital setting. To date, no research has examined behavioral measurement and cues that primary family caregivers respond to when assessing patients' level of distress arising from individual symptoms in the home setting. The qualitative data obtained from 37 primary family caregivers of patients with lung cancer was designed to augment quantitative results discussed elsewhere. Content analysis was performed on written responses to an open-ended questionnaire in which family caregivers identified cues that they responded to when assessing patients' distress from symptom items. The results identified the categories of impaired functioning and verbal cues as the most frequent indices of symptom distress. This study documents that certain behavioral measures for assessing symptom distress may be clinically useful to observers. Primary family caregivers are shown in this study to take a limited multidimensional approach in the assessment of patients' distress from symptoms.