At least a fifth of breast cancer cases in Western countries are likely to be due to modifiable lifestyle factors. Previous work has found that while women in Western countries are aware that breast cancer can be hereditary, their knowledge of the influence of lifestyle is poor. This survey investigated on the awareness of breast cancer risk factors in university students from 23 countries between 1999 and 2001. Data were collected on awareness of links with heredity, alcohol use, exercise, obesity, stress, smoking and diet. Almost a third of women were not aware that any of these factors influenced breast cancer. Just 57% were aware of the genetic link and fewer than 1 in 20 women correctly identified alcohol, exercise or obesity as factors influencing breast cancer. Stress and smoking were the most commonly chosen lifestyle risk factors although current data suggest that they have little actual impact on breast cancer risk. There was considerable international variation, with highest levels of awareness in students in the United States of America (USA). Knowledge of risk in this sample was poorer than previously observed in older women. Health messages concerning cancer in general may be more relevant for this age group, because of the lower salience of breast cancer for younger women.