Background: Caring for elderly cancer patients may cause multidimensional burden on family caregivers. Recognition of factors associated with caregiver burden is important for providing proactive support to caregivers at risk.; Objective: The aim of this study was to identify factors associated with high caregiver burden among family caregivers of elderly cancer patients.; Methods: A systematic search of 7 electronic databases was conducted from database inception to October 2014. The identified studies were screened, and full text was further assessed. The quality of included studies was assessed using a checklist, and relevant data were extracted using a predeveloped data extraction form. Best-evidence synthesis model was used for data synthesis.; Results: The search yielded a total of 3339 studies, and 7 studies involving 1233 family caregivers were included after screening and full assessment of 116 studies. Moderate evidence supported that younger caregivers, solid tumors, and assistance with patient's activities of daily living were significantly associated with high caregiver burden. Eighteen factors were supported by limited evidence, and 1 was a conflicting factor.; Conclusions: The scientific literature to date proved that caregiver burden was commonly experienced by family caregivers of elderly cancer patients. The evidence indicated that family caregivers who were at younger age, caring for solid tumor patients, and providing assistance with patient's activities of daily living reported high caregiver burden.; Implications For Practice: The data provide evidence in identifying family caregivers at high risk of high caregiver burden. More high-quality studies are needed to clarify and determine the estimates of the effects of individual factors.