Significance: Since the terrorist attacks of September 11, 2001 [9-11], terrorism poses a continuous threat to those living in the U.S. A substantial number of people may have experienced behavioral and life changes since the attacks with possible implications for public health. However, no study has examined the behavioral and life changes of individuals on a national scale. The purpose of this study was to investigate behavioral and life changes that American people have experienced since the 9-11 attacks. Methods: Using random-digit dialing that included unpublished numbers and new listings, a nationally representative sample of 807 U.S. adults ages 18 or older was interviewed about their behavioral and life changes since the 9-11 events. The interview was conducted by professional telephone interviewers at the Center for Survey Research (CSR) in Bloomington, IN, from July 23, 2002 to September 8, 2002, using the University of California Computer-Assisted Survey Methods software. The 60 interviewers who performed the telephone interviews were monitored for quality and comparability by five survey supervisors using specialized telephone lines and computer equipment, which do not allow the interviewers to know they are being monitored. The audio and visual monitoring was conducted randomly, with each interviewer being monitored at least once during each 3-hour shift. Results: Of the total respondents, 25% reported they have limited their outside activities; 24% turned more to prayer, religion, or spirituality; 23% changed mode of transportation; 15% gathered emergency supplies such as extra food, gas, or cash; 12% improved home security; and 10% considered buying a weapon, as a result of the 9-11 events. Logistic regression analyses indicated that gender, age, race/ethnicity, and employment status were significant predictors for experiencing different outcome variables. While women were more likely than men to turn to religion, limit outside activities, and change mode of transportation, women were less likely to consider purchasing a weapon. African Americans were more likely to turn to religion, gather emergency supplies, limit outside activities, change mode of transportation, and improve home security than Whites. The qualitative data obtained from an open-ended question regarding life changes revealed interesting clustering as well as reinforced the findings from closed-ended questions. For example, 80% of the respondents who reported feeling more patriotic were White females ages 42 to 54. Conclusions: The 9-11 events have considerably affected Americans’ lifestyles and behavior, which may have various implications to public health policy-makers and educators. Keyword(s): health promotion, interdisciplinary, national issues