In examining the response of local and State public health departments, this study involved interviews of officials from the six epicenters that experienced anthrax attacks. To study Federal public health efforts, officials were interviewed in the Department of Defense and the Department of Health and Human Services. The study was conducted from May 2003 through October 2003 in accordance with generally accepted government auditing standards. Officials at the local and State levels indicated that their planning efforts had helped to promote a rapid and coordinated response; however, they had not fully anticipated the extent of coordination that would be required across both public and private entities involved in the response to the anthrax incidents. Local and State officials emphasized the importance of effective communication throughout the incidents. They reported that communication among response agencies was generally effective, but they had difficulty reaching clinicians to provide them with needed guidance. Local and State public health officials were concerned that the capacity of their workforce and clinical laboratories was strained; they reported that their response would have been difficult to sustain if the incidents had been more extensive. At the Federal level, the Centers for Disease Control (CDC) was challenged to meet heavy resource demands from local and State officials and coordinate the Federal public health response in the face of rapidly evolving anthrax incidents. CDC acknowledged that although it was effective in its more traditional capacity of supporting local response efforts, it was not fully prepared to manage the Federal public health response. In addition to straining CDC's resources, the anthrax incidents exposed shortcomings in the clinical tools available for responding to anthrax (vaccines and drugs) and a lack of training for clinicians regarding identifying and responding to the disease. CDC has taken steps to make some improvements. These have included creating the Office of Terrorism Preparedness and Emergency Response within the Office of the Director, creating an emergency operations center, enhancing the agency's communication infrastructure, and developing databases of information and expertise on the biological agents considered likely to be used in a terrorist attack. CDC has also been working with other Federal agencies and private organizations to develop better clinical tools and increase training for medical care professionals. 1 table and appended timeline of selected key events in the anthrax incidents, comments from the Department of Defense, comments from the Department of Health and Human Services, and a list of General Accounting Office contact and staff acknowledgments