This paper presents trends over time in the number of children in particularly vulnerable families, including families facing risks such as domestic violence, child maltreatment, substance abuse, depression, and childhood disabilities. These families are of particular importance to policymakers given the considerable risk to children's safety and development, the challenges to parents' ability to support a family as well as raise children when they are facing these major stressors, and the potential requirement for strong public or community roles to meet children's needs when parents cannot.