The National Research Council's Disasters Roundtable and the Institute of Medicine's Roundtable on Environmental Health Sciences, Research, and Medicine were established as mechanisms for bringing various stakeholders together to discuss timely issues in a neutral setting. The goal was not to resolve these issues, but to create an environment conducive to scientific debate. The members of the respective Roundtables comprise representatives from academia, industry, nongovernmental agencies, and government, whose perspectives range widely and represent the diverse viewpoints of researchers, federal officials, and public interest. This report is the summary of a workshop was convened by the two Roundtables as a contribution to the debate on the health risks of disasters and the related need to build capacity to deal with them. The meeting was strengthened by integrating perspectives from these two fields, so that the agenda represented information from both communities and provided an opportunity to look at some of the most pressing research and preparedness needs for health risks of disasters.