Following the World Trade Center attack of September 2001 and the anthrax terrorism incident of October 2001, there has been a heightened interest in using surveys to assess our readiness for various disasters. Therefore, the U.S. Department of Health and Human Services, Office of the Assistant Secretary for Planning and Evaluation (ASPE), provided funding to the National Center for Health Statistics (NCHS) to survey hospitals about preparedness for treating patients from bioterrorism attacks or mass casualty incidents. Bioterrorism and Mass Casualty Preparedness Supplements were added to the 2003 and 2004 National Hospital Ambulatory Medical Care Surveys (NHAMCS). A preliminary report on hospital preparedness for bioterrorism or other mass casualties showed that hospitals were prepared in 2003 in most of the areas studied (1). Other more comprehensive publications covering both years followed (2–4).