Despite the recent decline in breast cancer mortality, African American women continue to die from breast cancer at higher rates than do White women. Beyond the fact that breast cancer tends to be a more biologically aggressive disease in African American than in White women, this disparity in breast cancer mortality also reflects social barriers that disproportionately affect African American women. These barriers hinder cancer prevention and control efforts and modify the biological expression of disease. The present review focuses on delineating social, economic, and cultural factors that are potentially responsible for Black-White disparities in breast cancer mortality. This review was guided by the social determinants of health disparities model, a model that identifies barriers associated with poverty, culture, and social injustice as major causes of health disparities. These barriers, in concert with genetic, biological, and environmental factors, can promote differential outcomes for African American and White women along the entire breast cancer continuum, from screening and early detection to treatment and survival. Barriers related to poverty include lack of a primary care physician, inadequate health insurance, and poor access to health care. Barriers related to culture include perceived invulnerability, folk beliefs, and a general mistrust of the health care system. Barriers related to social injustice include racial profiling and discrimination. Many of these barriers are potentially modifiable. Thus, in addition to biomedical advancements, future efforts to reduce disparities in breast cancer mortality should address social barriers that perpetuate disparities among African American and White women in the United States. (Cancer Epidemiol Biomarkers Prev 2008;17(11):2913 -23) During the last two decades, there has been a growing Black-White disparity in breast cancer mortality (1). Although the overall rate of mortality from breast cancer has been decreasing since the early 1980s, this decrease has occurred at a much faster pace for White women than it has for African American women (Fig. 1). This finding is especially noteworthy because the lifetime incidence of breast cancer is actually lower, not higher, among African American women than among their White counterparts (1).What factors might be responsible for this racial disparity in mortality from breast cancer? Poorer outcomes in African American women, in part, reflect the fact that breast cancer tends to be a more biologically aggressive disease in African Americans than in White Americans (2-6). In addition to biological factors, these disparities also reflect social, economic, and cultural barriers that disproportionately affect African American women. Barriers such as poverty and racism both hinder cancer prevention and control efforts and modify the biological expression of disease (7-10). The current review focuses on delineating the social, economic, and cultural factors potentially responsible for Black-White disparities i...