The purpose of this study were to determine if there are differences in the mood states, health status, and caregiver strain between family caregivers of oncology outpatients with and without cancer-related pain. A convenience sample of 86 family caregivers of patients with cancer-related pain and 42 caregivers of pain-free patients participated in this study. Family caregivers of patients with cancer-related pain scored significantly higher on the tension and depression subscales of the Profile of Mood States and had a significantly higher total mood disturbance score than did caregivers of pain-free patients. Although family caregivers of patients with pain had lower health status scores and higher caregiver strain scores than caregivers of pain-free patients, these differences were not statistically significant. The results of this study suggest that the presence of pain in a cancer patient adversely affect the mood states of family caregivers, particularly their level of depression and anxiety, and that health care professionals need to assess the psychological needs of family members caring for cancer patients experiencing pain.