Wealth, income, racial segregation, social networks, cultural knowledge and public policies affect entry into any particular housing niche (Saegert & Evans, 2003). Particular niches affect health exposure to environmental threats and resources. The effects of living in a particular niche over time affect the resources available across generations for entering new niches. An ecological model of the relationship between housing and health directs attention to nested levels of analysis (individuals within households, within buildings and blocks, within neighborhoods, within towns and cities, within larger social units). It also suggests the use of cumulative risk models and the investigation of mediation and moderation of more distant factors by those that are more proximal. Housing quality has direct effects on physical and mental health (Evan, Wells, & Moch, 2003; Saegert, Klitzman, Freudenberg, Cooperman-Mrozek, & Nassar, 2003). In addition, the housing niche model highlights how the non-housing components of particular niches affect individuals within a household and how the family dynamics related to living in stressful or hazardous niches affect child development and well-being. Thus housing policies can affect health through affecting housing quality, but also because of economic and social consequences of a particular housing situation, with further implications for family dynamics and health. Two studies are used to illustrate how the model may be employed in analyzing implications of different housing niches for health and development. The first study of New York City Housing Authority (NYCHA) developments which have been shown to be better maintained than other low-income housing in the city (Schill & Scafidi, 1996) included 40 families. It confirmed that housing quality did not contribute to psychological distress or stress for NYCHA families in this sample. However, the social and economic conditions experienced by NYCHA families had negative consequences for their well being. Among the forty participant households, the most salient stressors for children and parents differed. For children, community violence was the most stressful. About 75% of the children had seen people beaten and drug deals, and heard gunshots. These experiences were significant predictors of scores of psychological distress. Lower cardio-vascular activation, a symptom of post-traumatic stress, also related to exposure to violence. Economic strain was the most salient negative factor in mothers' levels of psychological distress and also related to the harshness of parenting. Violence exposure interacted with harshness of parenting in predicting diastolic blood pressure. Children exposed to both harsh parenting and violence had lower diastolic blood pressure than children in any other condition. When the interaction was taken into account, no main effects remained significant. In the second study 113 poor families in rural upstate New York, housing quality was often low, and significantly predicted both children and mothers’ psychological distress, and mothers’ reports of harsh parenting. In this sample as well, exposure to community violence and economic strain were negatively associated with children and mothers’ mental health. Mothers’ reports of more economic strain were also associated with higher systolic blood pressure in children. Analysis of the rural sample confirmed the critical role played by maternal psychological health in protecting children from environmental stressors. Mothers’ psychological distress was significantly related to children's distress. The effects of both violence and housing quality on children's psychological distress were fully mediated by maternal distress. Mothers’ psychological distress partially mediated the effect of economic strain on systolic blood pressure. These studies confirmed that economic strain, exposure to violence, and poor housing quality contributed significantly to stress levels of mothers and children. As expected, the niches differed in which stressors were experienced as most problematic. Mothers’ mental states and parenting were sensitive to external stressors and mediated or moderated the effects of stressors on children. Public policy implications of these studies and of an experiment in randomly assigning public housing families to better, worse or the same neighborhoods are discussed. Social structural barriers that undermine the effectiveness of many health and housing interventions are considered.