To improve breast cancer control among Latinas, it is important to understand culturally based beliefs that many influence the way women view this disease. We did a telephone survey of randomly selected Latinas and non-Hispanic white (Anglo) women in Orange County, California, to explore such beliefs using questions from previous national surveys and an ethnographic study of breast cancer. Respondents included 803 Latinas and 422 Anglo women. Latinas were more likely than Anglo women to believe that factors such as breast trauma (71% versus 39%) and breast fondling (27% versus 6%) increased the risk of breast cancer, less likely to know that symptoms such as breast lumps (89% versus 98%) and bloody breast discharge (69% versus 88%) could indicate breast cancer, and more likely to believe that mammograms were necessary only to evaluate breast lumps (35% versus 11%) (P < .01 for each). After adjusting for age, education, employment status, insurance status, and income, logistic regression analysis confirmed that Latino ethnicity and acculturation levels were significant predictors of these beliefs. We conclude that Latinas' beliefs about cancer differ in important ways from those of Anglo women and that these beliefs may reflect the moral framework within which Latinas interpret diseases. These findings are important for the development of culturally sensitive breast cancer control programs and for practicing physicians.