The growing awareness of the impact of natural disasters on human communities has raised awareness of the need for better measurements and models of vulnerability to disasters and for improved management of information that guides the humanitarian response. This paper describes an integrated approach to disaster assessment that will enhance the understanding of vulnerability and provide information for decision making in the post-disaster context. The study is a multidisciplinary approach that brings together the fields of physical science, demography, public health, and informatics. Modeling population vulnerability and risk in natural disasters, in conjunction with post-disaster assessments of surviving populations will enable governments and humanitarian organizations to make more informed decisions in terms of how to locate need and allocate resources in the aftermath of disasters. A case study on a post-earthquake assessment in Peru is presented. Copyright ASCE 2008.