Abstract As clinical guidelines for cancer prevention refer individuals to primary care physicians (PCP) for risk assessment and clinical management, PCPs may be expected to play an increasing role in cancer prevention. It is crucial that PCPs are adequately supported to assess an individual’s cancer risk and make appropriate recommendations. The objective of this study is to assess use, familiarity, attitude, and behaviors of PCPs regarding breast and ovarian cancer risk and prevention, to better understand the factors that influence their prescribing behaviors. We conducted a cross-sectional, web-based survey of PCPs in the United States, recruited from an opt-in healthcare provider panel. Invitations were sent in batches until the target sample size of 750 respondents (250 each for obstetrics/gynecology, internal medicine, and family medicine) was met. Self-reported use of breast/ovarian cancer risk assessments was low (34.7%–59.2%) compared with discussion of cancer family history (96.9%), breast exams (87.1%), and mammograms (92.8%). Although most respondents (48.0%–66.8%) were familiar with cancer prevention interventions, respondents who reported to be less familiar were more likely to report cautious attitudes. When presented with hypothetical cases depicting patients at different breast/ovarian cancer risks, up to 34.0% of respondents did not select any of the clinically recommended course(s) of action. This survey suggests that PCP use of breast/ovarian cancer risk assessment tools and ability to translate the perceived risks to clinical actions is variable. Improving implementation of cancer risk assessment and clinical management guidelines within primary care may be necessary to improve the appropriate prescribing of cancer prevention interventions. Prevention Relevance: Primary care physicians are becoming more involved in cancer prevention management, so it is important that cancer risk assessment and medical society guideline recommendations for cancer prevention are better integrated into primary care to improve appropriate prescribing of cancer prevention interventions and help reduce cancer risk.