Data from the 1993 to 1995 waves of the Asset and Health Dynamics among the Oldest Old were used to analyze unmarried elderly parents' and children's characteristics associated with their respective self-reported reasons for coresidence: always lived together, to help the child, to help the parent, or to help both. As compared to the parents in the always-lived-together pairs, parents as the help receivers were older, had more health problems, and were more likely to have moved in with an older, married child. Children as the help recipients were more likely to be sons than daughters and less likely to work or make a financial contribution to the household. Parents in the mutual-help group were more likely to have higher education and to have been divorced, separated, or never married than to be widowed, and the children were more likely to be married. Parental gender and race/ethnicity were not significant factors.