Informed consent for BRCA1 mutation testing will require adequate knowledge of patterns of inheritance of cancer and the benefits, limitations, and risks of DNA testing. This study examined knowledge about the inheritance of breast cancer and attitudes about genetic testing for breast-ovarian cancer susceptibility in women at increased risk. Knowledge and attitudes were measured in 407 African American and Caucasian women aged 18-75 who had at least one first-degree relative (FDR) with breast and/or ovarian cancer. The average knowledge score was 6.0 out of a total of 11 (S.D. = 2.15). Compared to Caucasian women, African American women had lower levels of knowledge and had more positive attitudes about the benefits of genetic testing. There were no significant ethnic differences in attitudes about the limitations and risks of testing, however, income was negatively associated with this outcome. Ethnic differences in knowledge and attitudes about genetic testing for breast-ovarian cancer risk may be attributable to differences in exposure to genetic information and referral by health care providers.