Background: Family caregivers provide the majority of health care to the 18 million persons with cancer in the U.S. Yet despite providing complex medical and nursing care, a large proportion report no formal support or training. Recognizing this gap, many interventions to support cancer caregivers have been developed and tested over the past two decades and many have demonstrated effectiveness. However, there is little system-level data on whether U.S. cancer centers have adopted and implemented these interventions. We conducted the first national survey of Commission on Cancer (CoC)-accredited U.S. cancer centers to characterize the availability and types of family caregiver support programs. Methods: We conducted a mail and web-based survey of staff from CoC-accredited U.S. cancer centers regarding their family caregiver support programs (09/2021-03/2023). “Family caregiver programs” were defined as structured, planned, coordinated groups of activities and procedures aimed specifically at supporting family caregivers as part of usual care. Survey questions about 11 types of family caregiver programs (e.g., peer-mentoring, education classes, psychosocial programs) were developed after literature review, assessment of similar program evaluation surveys, and discussions among a 13-member national expert advisory committee. Results: Surveys were sent to potential respondents at 971 adult cancer centers and 238 were completed (response rate: 25%). Most cancer centers had at least 1 family caregiver program (178/238, 75.1%), which was most commonly “Information and Referral Services” (53.4%). Cancer centers with no programs were more likely to have smaller annual outpatient volumes (p<.05). Few centers had caregiver programs on: training in medical and/or nursing tasks (21.8%), caregiver self-care (20.3%), caregiver-specific distress screening (19.3%), peer mentoring (18.5%), and minor children caregiving for a parent (8.4%). Very few programs were developed from published evidence in a journal (7.9%). The top reason why cancer centers chose their programs was community members requesting the program (26.5%); only 11.8% chose their programs based on scientific evidence. Most programs were funded by the cancer center or hospital (58.0%) or by philanthropy (42.4%). Conclusions: While most U.S. cancer centers had some family caregiver programs, a quarter had none. Furthermore, the scope of programming was limited and rarely evidence-based, with few centers offering caregiver education and training. Implementation strategies are critically needed to foster uptake of evidence-based caregiver interventions.