Background: As adults with intellectual and developmental disabilities (IDD) have longer lives, parents may remain caregivers into old age. In addition, it is unknown who will fulfil caregiving roles after parents are no longer able to be caregivers. In the current study, we explored the nature (e.g. number of hours of caregiving) and correlates of parental caregiving for their adult offspring with intellectual and developmental disabilities and their future caregiving plans. Method: In the United States, data were collected from 334 parents of adults with intellectual and developmental disabilities via a national survey. Results: Altogether, 55% of the sample spent more than 15 hr conducting caregiving per week. Individual characteristics (e.g. maladaptive behaviour and functional abilities) and parent characteristics (e.g. physical proximity of the adult with intellectual and developmental disabilities and caregiving ability) positively correlated with caregiving hours. Notably, 38.58% of participants were unsure who would fulfil caregiving roles. Conclusion: Implications for research about caregiving and practice are discussed.