Substantial public interest in receiving a smallpox vaccination grows in part from continuing fears about a future bioterrorist attack. Nine months after the September 11th attacks, more than four in 10 (43 percent) of Americans surveyed in the summer of 2002 reported being worried about a future attack using smallpox, down from 53 percent in November 2001. In the near run, the public sees little risk that they or a family member will get smallpox. Only one in 12 Americans (8 percent) believes that they or someone in their immediate family is likely to contract smallpox during the next 12 months. This compares with 20 percent who believe they or a family member are likely to be injured in some other type of terrorist attack. Most Americans (74 percent) are at least mildly optimistic that they would survive if they contracted smallpox and received immediate medical care. This study is the third in a series by the Harvard School of Public Health/Robert Wood Johnson Foundation Survey Project on Americans’ Response to Bioterrorism. The project director is Robert J. Blendon of the School of Public Health.