This article presents the results of new data collection in Mexico about the relationship between child well-being and social networks. Two research questions guide the analysis. First, under what conditions do networks generate greater (lesser) support? Second, what kinds of networks are associated with healthier children? We explore the health status effects of several dimensions of social networks, including network size, kinship roles, interaction (proximity, contact, and coresidence), and provision of financial and emotional support. Our key findings suggest that networks containing more extended kin and coresident ties offer greater support resources to mothers with young children, especially among the poorest households. We also find that network structures characterized by more social support and greater interaction with extended, rather than immediate, kin help sustain healthier children. Together these findings indicate the advantages of examining specific role relationships in network research among economically marginalized families and attest to the importance of social networks founded on principles of reciprocity, confianza, and compadrazgo to the well-being of Mexican families.