During natural disasters, disease pandemics, terrorist attacks, and other public health emergencies, the health system must be prepared to accommodate a surge in the number of individuals seeking medical help. For the health community, a primary concern is how to provide care to individuals during such high demand, when the health system's resources are exhausted and there are more patients than the system can accommodate. The IOM's Forum on Medical and Public Health Preparedness for Catastrophic Events held a workshop June 10-11, 2009, to assess the capability of and tools available to federal, state, and local governments to respond to a medical surge. In addition, participants discussed strategies for the public and private sectors to improve preparedness for such a surge. The workshop brought together leaders in the medical and public health preparedness fields, including policy makers from federal agencies and state and local public health departments; providers from the health care community; and health care and hospital administrators. This document summarizes the workshop.