Although tamoxifen has been approved by the Food and Drug Administration for primary prevention of breast cancer since 1998, studies suggest that use by high-risk women is limited. Primary care providers play a key role in the prescription of tamoxifen for primary prevention because most eligible women will not be seen in high-risk clinics. In this survey of 350 primary care providers, Armstrong et al found that 27% of providers had prescribed tamoxifen in the past 12 months. Providers who had prescribed tamoxifen were more likely to have a family member with breast cancer, to have patients ask for information about tamoxifen, and to believe that the benefits of tamoxifen outweighed the risks and that determining eligibility was easy. In hypothetical scenarios of women with different risk profiles, the prescription of tamoxifen was affected by the patient's family history of breast cancer but not her endometrial cancer risk (ie, hysterectomy status). These results indicate that increasing the uptake of chemoprevention will require addressing logistical issues and physician and patient motivation as well as improving the risk-benefit ratio of the intervention.