Drawing on the family process literature, child health models, and recent studies of macro-level effects on health, we examine the effects of household structure, resources, care-giving, reproduction, and communication on child nutritional status and infant mortality. Using Demographic and Health Surveys, we analyze the influence of these factors across 42 countries in Latin America, Africa, and Asia. We also consider country-level including nontraditional family structure, level of economic development and expenditures on health care. Our results underscore the importance of family resources, decision-making, and health and feeding practices on child well-being in less developed countries. Although there is cross-national variability, the size of the variability was small relative to the overall effect. The country-level measures had modest effects on infant mortality and child nutritional status.