Some poor families live in worse neighborhoods than others, and some live in worse housing conditions than others.  What explains these differences?  Since mounting evidence documents the consequential and long-lasting effects of housing and neighborhood characteristics on the wellbeing and life chances of low-income adults and children, determining how poor families choose to live where they do is crucial to our understanding of the root causes of social disadvantage and to the development of effective policy initiatives.  And yet surprisingly little attention has been paid to housing and neighborhood selection among the urban poor.  Drawing on novel data—that from the Milwaukee Area Renters Study, an original survey completed in 2011 of more than 1,000 low-income rental households in Milwaukee—this study investigates why poor families move, how they locate and housing, and the degree to which these factors, in addition to their characteristics (e.g., their race, employment, criminal record) and those of their social network (e.g., its size, location, resources), affect their housing and neighborhood quality.  By examining not only renters’ reason for moving (e.g., voluntary or involuntary) but also the strategies by which they locate housing, we are able to identify multiple mechanisms that help explain why poor families live where they do (neighborhood characteristics: crime, concentrated poverty, racial segregation) and live in what they do (housing selection: chronic and dangerous housing problems, overcrowded conditions, rent and energy costs).  This study holds several implications for housing and poverty policy.