Increasing urbanization has resulted in a faster growth of slum population. Various agencies, especially those in developing countries are finding it difficult to respond to this situation effectively. Disparities among slums exist owing to various factors. This has led to varying degrees of health burden on the slum children. Child health conditions in slums with inadequate services are worse in comparison to relatively better served slums. Identification, mapping and assessment of all slums is important for locating the hitherto missed out slums and focusing on the neediest slums. In view of the differential vulnerabilities across slums, an urban child health program should build context appropriate and community-need-responsive approaches to improve children's health in the slums.