Few studies have examined how experiences associated with being an undocumented immigrant parent affects children's development. In this article, the authors apply social exclusion theory to examine how access to institutional resources that require identification may matter for parents and children in immigrant families. As hypothesized, groups with higher proportions of undocumented parents in New York City (e.g., Mexicans compared to Dominicans) reported lower levels of access to checking accounts, savings accounts, credit, and drivers' licenses. Lack of access to such resources, in turn, was associated with higher economic hardship and psychological distress among parents, and lower levels of cognitive ability in their 24-month-old children. (Contains 1 table, 6 figures, and 2 footnotes.)