Objective: The purpose of this study was to describe distressed and underprepared family caregiver's use of and interest in formal support services (eg, professional counseling, education, organizational assistance). Method: Cross-sectional mail survey conducted in communities of 8 cancer centers in Tennessee, Alabama, and Florida (response rate: 42%). Family caregivers of Medicare beneficiaries with pancreatic, lung, brain, ovarian, head and neck, hematologic, and stage IV cancers reported support service use and completed validated measures of depression, anxiety, burden, preparedness, and health. Results: Caregivers (n = 294) were on average age 65 years and mostly female (73%), White (91%), and care recipients' spouse/partner (60%); patients averaged 75 years were majority male (54%) with lung cancer (39%). Thirty-two percent of caregivers reported accessing services while 28% were "mostly" or "extremely" interested. Thirty-five percent of caregivers with high depressive symptoms (n = 122), 33% with high anxiety symptoms (n = 100), and 25% of those in the lowest quartile of preparedness (n = 77) accessed services. Thirty-eight percent of those with high depressive symptoms, 47% with high anxiety symptoms, and 36% in the lowest quartile of preparedness were "mostly" or "extremely" interested in receiving services. Being interested in support services was significantly associated with being a minority, shorter durations of caregiving, and with higher stress burden. Conclusions: A large proportion of family caregivers, including those experiencing depression and anxiety symptoms and who were underprepared, are not using formal support services but have a strong interest in services. Strategies to increase service use may include targeting distressed caregivers early in their caregiving experience.