A challenge for health behavior science is to develop theory and best practices that take cultural diversity into account. Using data from Black, Hispanic, and White respondents to the 2003 Health Information National Trends Survey, we examined racial/ethnic differences in: (1) breast cancer risk perceptions/worry; (2) the associations between perceived risk/worry and ever having received a mammogram; and (3) perceived risk/worry and having had at least 2 mammograms over a 4-year period (consecutive mammography). Compared to White race/ethnicity, Black race/ethnicity was associated with lower perceived absolute risk and comparative risk for developing cancer. For the sample as a whole, higher perceived risk (both absolute risk and comparative risk) and worry predicted greater odds of mammography use; however, this was not true for Hispanics. In stratified analyses, perceived risk and worry were not associated with mammography use for either Hispanics or Blacks whereas they were for Whites; however, this interaction effect was significant only for Hispanics vs. Whites. Results support the need for formative research to identify determinants of health behavior prior to cancer prevention message planning for diverse audiences in order to accommodate racial/ethnic differences not only in the level of perceived risk, but also the association between risk perception to behavior change in that community.