This secondary data analysis of 4373 mothers and their children investigated racial disparities in children's health and its associations with social structural factors, social relationships/support, health/mental health, substance use, and access to health/mental health services. The study drew on longitudinal records for mother-child pairs created from data in the Fragile Families and Child Wellbeing Study. Generalized estimating equations yielded results showing children's good health to be associated positively with mother's health (current health and health during pregnancy), across three ethnic groups. For African-American children, good health was associated with mothers' education level, receipt of informal child care, receipt of public health insurance, uninsured status, and absence of depression. For Hispanic children, health was positively associated with mothers' education level, receipt of substance-use treatment, and non-receipt of public assistance. Implications for policy and intervention are discussed.