A workshop on Modeling and Simulation for Emergency Response was held from March 4 to March 6, 2003 at NIST. The workshop program included talks and four breakout sessions that invited attendees to formulate recommendations in selected areas. The talks focused on topics ranging from requirements for modeling and simulation (M&S) tools for emergency response, proposals for integration of such tools into a framework for rapid deployment of this vital capability, currently available M&S applications for the purpose and funding programs to support such developments. This document summarizes the key points from the talks and workshop breakout sessions. The appendices provide related information on modeling and simulation and supporting tools, standards associated with this area and reference information.