Objectives:To describe informal caregiver and patient characteristics associated with high caregiver burden in homebound elders and to examine associations between high caregiver burden and patient health care utilization at the practice level. Method: We used a cross-sectional and prospective cohort design to study 214 caregiver-patient dyads in a home-based primary care program. Results: Informal caregivers with the highest burden were more likely to help with more activities of daily living and instrumental activities of daily living and spend >40 hr/week in caregiving. Patients whose caregivers experienced the highest burden were more likely to be non-White males without 24-hr paid homecare. There were no significant independent associations between high burden and high calls, high visits, or social work involvement. Discussion: In this medically complex and highly dependent population, further study of how families and other caregivers impact health care utilization is needed.