AbstractA conceptual model of the impact of structural advantage and disadvantage on infant mortality rates is developed and fitted to countylevel data. This model includes mediating endogenous constructs representing medical care availability, the incidence of teenage childbearing, and low birthweight rates and is estimated for three residence categories. Both direct and indirect effects of social structure and teenage childbearing on infant mortality vary significantly across the categories. Structural advantage exerts a significant and negative direct effect on infant mortality rates in urban areas, but in rural areas this effect is indirect, operating through teenage childbearing and low birthweight. Structural disadvantage significantly increases infant mortality in both rural and urban settings, but the effects operate directly in metropolitan areas and indirectly in rural areas. These results underscore the central role that social structure continues to play in determining infant mortality rates in the United States.