A large number of women in the population are at risk for the development of breast cancer. Methods now exist to accurately assess risk and to provide quantitative estimates of the chance of a woman developing breast cancer in her lifetime. Histologic assessment of premalignant breast pathology aids in the evaluation of risk. The availability of primary chemoprevention clinical trials reduces the number of indications for prophylactic mastectomy. Women at risk for breast cancer and women who have had a malignant lesion at another anatomic site have an increased risk for new cancers at multiple sites. We propose screening strategies based on epidemiologic information about the risks of these diseases and on the predictive value of the available screening tests. The merits and inadequacies of specific management strategies are considered. We review the risks and benefits of estrogen replacement therapy for women at increased risk for breast cancer and consider the ethical implications of both risk assessment and the various interventions.