Objectives: This study examined health care cost outcomes resulting from a health education program (HEP), a social work intervention for spouse caregivers of frail older adults. Method: One-hundred five spouses were recruited and randomly assigned to HEP or usual care (UC). Health care utilization and cost data were collected from the HMO's management information system for both the spouse caregivers and care recipients in quarterly increments for a 30-month period. Results: The results indicate that HEP was cost-effective. Caregivers and care recipients who participated in HEP had significantly lower overall health care costs and significantly lower outpatient costs than those who participated in usual care. Conclusions: By 2 years, total cost savings for caregivers and care recipients who participated in HEP was $309,461.14. HEP is a cost-effective intervention for caregivers and care recipients receiving medical care from a staff-model HMO. (Contains 5 tables.)