Although planning decisions have profound public-health implications, planning-health linkages have received relatively little attention in recent decades. Moreover, on the few occasions when such connections have been made, health outcomes have been narrowly construed, ignoring a wide array of well-documented linkages between the physical environment and human health. Planning decisions directly influence the character and quality of housing and neighborhoods including the external density of communities, the presence and size of parks, air and water quality, land-use mix, the height and size of residential structures, transit-mode mix, traffic density, retail-store location, road geometry, and community noise levels. Environmental characteristics of home and neighborhood, in turn, directly or indirectly affect physical health and psychological well-being. This paper presents a framework for considering the impact of planning decisions on a wide range of health issues. Empirical data from medical and social sciences illustrate connections between health outcomes among residents and residential-environment characteristics influenced by planning. This paper presents a critical summary of the current knowledge and the quality of the evidence. Where appropriate, we also note theoretically plausible leverage points where planning decisions may affect health, but which require further research to test their effects on health-related outcomes.