This paper examines the effects of family and neighborhood factors on child health in one of the largest urban areas in the United States, Los Angeles County. We use data from a new representative survey of neighborhoods and households in L.A. — the Los Angeles Family and Neighborhood Survey, or L.A.FANS — to examine the effects of family and neighborhood characteristics on child health status. A particular focus is on differences between Latinos and other race/ethnic groups as well as differences by duration of family residence in the U.S. and other key factors. We seek to answer two questions. First, how are family background factors such immigrant status, ethnicity, and social class related to child health outcomes? Second, are there differences in health outcomes by neighborhood-level socioeconomic status, once individual and family differences are held constant? Among the child health outcomes we examine are the mother’s report of the child’s overall health status, reports of physician diagnoses of key chronic diseases (such as anemia and asthma), and, among children aged 12-17 years, body mass index adjusted for age as well as indicators of being overweight or at risk of overweight.