Informal caregiving accounts for more than 75% of care hours provided in noninstitutional settings in the US. Caregivers often experience care-related stress, with consequences including decisions to end caregiving and institutionalization of the care recipient. This study examines the association of high levels of stress with nursing home entry and days of care and potential savings from successful caregiver support interventions, using data from administrative files linked to a nationally representative cohort of Medicare beneficiaries age 65 or older and their primary caregivers. High stress was a large and highly significant predictor. Simulations indicate that if caregiver support strategies could reduce stress below the threshold used in the study, up to one third of longer-stay admissions and 36% of expected days over one year could be avoided. Implied 1-year nursing home savings at current rates range from about $730 million to $1 billion, depending on intervention targeting.