Rising rates of nonmarital childbirth in the United States have resulted in a new family type, the fragile family. Such families, which include cohabiting couples as well as single mothers, experience significantly higher rates of poverty and material hardship than their married counterparts. Ariel Kalil and Rebecca Ryan summarize the economic challenges facing mothers in fragile families and describe the resources, both public and private, that help them meet these challenges. The authors explain that the economic fragility of these families stems from both mothers' and fathers' low earnings, which result from low education levels, as well as from physical, emotional, and mental health problems. Mothers in fragile families make ends meet in many ways. The authors show that various public programs, particularly those that provide in-kind assistance, do successfully lessen economic hardship in fragile families. Single mothers also turn to private sources of support--friends, family, boyfriends--for cash and in-kind assistance. But though these private safety nets are essential to many mothers' economic survival, according to the authors, private safety nets are not always consistent and dependable. Thus, assistance from private sources may not fundamentally improve mothers' economic circumstances. Policy makers, say Kalil and Ryan, must recognize that with rates of nonmarital childbirth at their current level, and potentially rising still, the fragile family is likely an enduring fixture in this country. It is thus essential to strengthen policies that both support these families' economic self-sufficiency and alleviate their hardship during inevitable times of economic distress. The most important first step, they say, is to strengthen the public safety net, especially such in-kind benefits as food stamps, Medicaid, housing, and child care. A next step would be to bolster community-based programs that can provide private financial support, such as emergency cash assistance, child care, and food aid, when mothers cannot receive it from their own private networks. (Contains 1 figure, 2 tables and 70 endnotes.)