Background: Despite the important role that family members can play in dementia care, little is known about the association between the availability of family members and the type of care, informal (unpaid) or formal (paid), that is actually delivered to older adults with dementia in the US. Results: Using data about older adults with dementia from the Health and Retirement Study, we found significantly lower spousal availability but greater adult child availability among women versus men, non-Hispanic Blacks versus non-Hispanic Whites, and people with lower versus higher socioeconomic status. Adults with dementia and disability who have greater family availability were significantly more likely to receive informal care and less likely to use formal care. In particular, the predicted probability of a community-dwelling adult moving to a nursing home during the subsequent two years was substantially lower for those who had a co-resident adult child (11 percent) compared with those who did not have a co-resident adult child but had at least one adult child living close (20 percent) and with those who have all children living far (23 percent). Conclusions: Health care policies on dementia should consider potential family availability in predicting the type of care that people with dementia will use and the potential disparities in consequences for them and their families.