Although the effectiveness of mammography for women under the age of 50 years with a family history of breast cancer (FHBC) has not yet been proven, annual screening is being offered to these women to manage breast cancer risk. This study investigates women's awareness and interpretation of their familial risk and knowledge and views about mammographic screening. A total of 2231 women from 21 familial/breast/genetics centres who were assessed as moderate risk (17-30% lifetime risk) or high risk (>30% lifetime risk) completed a questionnaire before their mammographic screening appointment. Most women (70%) believed they were likely, very likely or definitely going to develop breast cancer in their lifetime. Almost all women (97%) understood that the purpose of mammographic screening was to allow the early detection of breast cancer. However, 20% believed that a normal mammogram result meant there was definitely no breast cancer present, and only 4% understood that screening has not been proven to save lives in women under the age of 50 years. Women held positive views on mammography but did not appear to be well informed about the potential disadvantages. These findings suggest that further attention should be paid to improving information provision to women with an FHBC being offered routine screening.