First-degree relatives (FDRs) of women with breast cancer may have heightened anxiety about their personal risk for developing breast cancer. Breast self-examination (BSE) is an important component of risk surveillance for all women. In this study, the authors describe a subset of FDRs who appear to excessively (> or = once per day) perform BSE. These women, who constituted 8% of 1,053 FDRs in this study, were compared with women who did not examine excessively. The excessive self-examiners were older, more frequently African American, and less educated. They were more likely to have an affected daughter and > or = two FDRs with breast cancer. They were significantly more likely to think frequently about breast cancer and to report that such thoughts affected their mood. In a multivariate analysis, three variables had significant independent associations with excessive BSE practice: ethnicity (odds ratio [OR] = 2.3), perceived risk of breast cancer compared with women without a family history (OR = 2.9), and frequency of thoughts about breast cancer (OR = 5.5). The women who practice excessive BSE would benefit from enhanced educational efforts and screening for the presence of psychiatric problems such as anxiety and hypochondriasis.