This study examined predictors of older adults' and primary caregivers' willingness to use formal long-term care (LTC) services to understand possible use patterns of mandatory public LTC insurance programs in Korea. It focused on views regarding who (adult children or the government) should bear the responsibility for older adults' care. Logistic regression models were estimated using data from 1,168 older Korean adults aged 65 or older and their primary caregivers from a national survey. The results showed that older adults' and their caregivers' views on care responsibility were a dominant predictor of their willingness to use both formal home care services and nursing home care services. Both older adults and their family caregivers' willingness to use LTC services should be considered when predicting demand for LTC services. Efforts should promote the perspective that formal LTC services are an acceptable social norm.