More than 39,600 American women will die of breast cancer in 2013. The strongest risk factors for breast cancer are older age, family history of breast or ovarian cancer (especially in a mother, sister, or daughter before age 50 years), previous breast biopsy (especially if results showed an abnormality called “atypical hyperplasia”), and extremely dense breast tissue. Chemoprevention is a strategy for reducing the risk for cancer by taking drugs. Some evidence indicates that tamoxifen and a similar drug, raloxifene, can prevent breast cancer in women who have never had the disease. However, these drugs also have adverse effects, including hot flashes, and they increase the risk for uterine cancer, cataracts, and blood clots. Women must weigh the potential benefits of chemoprevention for breast cancer against these risks. The USPSTF last issued recommendations on breast cancer chemoprevention in 2002.