Genetic screening for BRCA1 and BRCA2 gives women the opportunity for early detection, surveillance, and intervention. One key feature of genetic testing and counseling is the provision of personal lifetime risk. However, little attention has been paid to how women interpret lifetime risk information, despite the fact that they base screening, treatment and family planning decisions on such information. To study this vital issue, we set out to test the ability of women to choose the most appropriate interpretation of National Cancer Institute’s (NCI) message about lifetime risk of developing cancer for a woman with altered BRCA1 and BRCA2 genes. Participants included 277 women who had not undergone genetic testing or had cancer and 207 women who had undergone genetic testing or had cancer. Over 50% of the women who had not undergone genetic testing or had cancer and 40% of those who had undergone genetic testing or had cancer misunderstood NCI’s information. Furthermore, in line with a growing body of research, we found that high numeracy level (objective or subjective) is positively associated with a woman’s ability to correctly interpret NCI’s message.