Young children spend more than 90% of their time in the household environment-a likely place of exposure to hazardous substances. In the developing world, childhood diarrheal disease and acute lower respiratory infections represent a large portion of the global burden of disease and are strongly related to housing conditions. In the developed world, allergies and asthma are also strongly linked to housing conditions. Therefore, intervention to improve housing is essential to improve and maintain children's health. This paper will review several factors that have been shown to mediate housing and health relations, including psychosocial, environmental, socioeconomic, behavior-cultural, and physiological factors, and will provide examples of intervention to improve child health, with housing as a focus. Environmental contaminants found in the household include biological (for example, vector-borne diseases, dustmites, mold, water and sanitation-related), chemical (for example, lead, volatile organic compounds, asbestos) or physical (for example, radon, electric and magnetic fields). Socioeconomic factors include bousehold income, the ability to obtain adequate and appropriate housing, and the ability to implement ongoing preventative maintenance. Housing tenure has been used as a proxy for socioeconomic status and shown some relation with health outcome. Socioeconomic factors can be relevant to the ability of households to create social networks that affect bealth. Psychosocial factors, including stress and depression, can also be related to housing type or design. Behavioral-cultural factors include practices that might influence exposure to chemical, biological, or radiation hazards like time-activity patterns, including gender relations and household decision-making patterns. Physiological factors include genetics or the nutritional and immune status of household members, which can influence the extent to which other housing factors like biological or chemical contaminants adversely affect children. Examples of intersectoral interventions and strategies to improve child health globally, with housing and health as a focus, include integrated pest-management programs to control vector-borne diseases like malaria and Chagas disease and energyefficiency programs to improve thermal comfort and to reduce the presence of allergens like mold and dustmites. Other interventions include housing and health policy, regulation and standard setting, education, training, and participation.