There are conflicting data on breast cancer awareness and knowledge in specific population groups. We assessed awareness and knowledge of breast cancer in the general Irish population to identify sources of information on breast cancer and determine factors associated with knowledge and awareness of the disease. Participants (n=2355, 53% female) completed a multi-part questionnaire. Most (81%) had seen or heard something about breast cancer in the recent past and knowledge of symptoms and treatment was good overall. However, 66% of females overestimated their risk of developing disease, 88% underestimated the age at which it was most likely to develop and 56% underestimated 5-year survival. Knowledge of incidence and survival was higher in males (Odds Ratio (OR) 1.3, 95% Confidence Interval (CI); 1.1-1.5), participants with higher education (1.5; 1.2-1.7) and those who received information from television (1.3; 1.1-1.5). Ignorance regarding incidence, outcome and risk makes it unlikely that the general public or at risk females could currently make informed decisions on a range of breast cancer issues.