In November 2013, the U.S. Preventive Services Task Force issued a guideline on medications for risk reduction of primary breast cancer in women. Although mammography can detect early cases, it cannot prevent development of breast cancer. Tamoxifen and raloxifene are selective estrogen receptor modulators that have been shown to reduce the risk for estrogen receptor–positive breast cancer and are approved by the U.S. Food and Drug Administration (FDA) for this indication. However, neither medication reduces the risk for estrogen receptor–negative breast cancer or all-cause mortality. The Task Force concluded that postmenopausal women with an estimated 5-year risk for breast cancer of 3% or greater will probably have more net benefit than harm and recommends that clinicians engage in shared, informed decision making about these medications. The American Society of Clinical Oncology issued a practice guideline on use of pharmacologic interventions for breast cancer in 2013. It recommends that women aged 35 years or older at increased risk, defined as a 5-year absolute risk for breast cancer of 1.66% or greater, discuss breast cancer prevention medications with their primary care practitioner. The Society includes the aromatase inhibitor exemestane in addition to tamoxifen and raloxifene as a breast cancer prevention medication, although exemestane is not FDA approved for this indication. Here, an oncologist and an internist discuss how they would balance these recommendations and what they would suggest for an individual patient.