Depression affects millions of Americans each year and bears significant societal and financial costs. However, it is estimated that only 25 percent of individuals with depression receive appropriate care. Given that women are almost twice as likely as men to experience depression, and that the majority of women age 15 to 50 have children, maternal depression is an important and potentially costly issue. RAND examined evidence on the impact of maternal depression on the mother and child as it relates to the public sector systems that serve them; specifically, public assistance, physical health, early intervention, education, and child welfare. Although the potential costs associated with untreated maternal depression may be reduced or eliminated by focusing additional resources on the identification and treatment of depression, prevention efforts to reduce risk for, and incidence of, maternal depression may prove to be just as valuable if not more cost-effective. This report discusses potential short- and long-term cost implications, and is intended to serve as a source of information for state and local policymakers and practitioners concerned with child and family outcomes to inform them of the evidence connecting maternal depression and negative outcomes for mother and child.