Family caregivers encounter immense negative consequences including decreased quality of life and increased rates of morbidity and mortality that stem from physical burdens, emotional distress, depression, social isolation, and loss of financial security. Although communication is an important aspect of caregiving, communication tasks are reportedly difficult for end-of-life family caregivers. The goal of this study was to explore the variety of communication stressors experienced by end-of-life family caregivers to gain insight into the communication tasks caregivers perceive as most difficult and the reasons why. Qualitative data was achieved through in-depth, face-to-face interviews with 40 caregivers currently providing care for a family member diagnosed with Alzheimer’s disease and related dementias (n=20; ADRD) and Glioblastoma (n=20; brain tumor [GBM]). A grounded theory approach was employed to gain insight into end-of-life family caregiver communication experiences. The results revealed that communication is perceived as a burden for end-of-life family caregivers. Not only does communication burden exist, end-of-life family caregivers experience immense tension and stress regarding a variety of relational contexts when communicating with the care recipient, others (family, friends), and clinicians. The results further revealed that communication burden stems from the caregiver’s attempt to negotiate between two opposing extremes: a desire to protect the patient and others versus a need to protect oneself. Thus, internal tension occurs when end-of-life family caregivers contemplate whether and how to engage in difficult conversations, and then again when following through. The presence of these contradictory tensions induced the emergence of barriers and therefore communication burden within various aspects of the end-of-life caregiver experience. Added insight into communication burden was achieved through a supplementary scale development study in a sample of ADRD and oncology end-of-life caregivers (N=263), which revealed communication burden as significantly associated with caregiver burden and quality of life. Implications for the advancement of interpersonal and health communication theory as well as practical tailored interventions targeting end-of-life family caregivers are discussed.