The appropriate management of breast cancer risk in BRCA mutation carriers following ovarian cancer diagnosis remains unclear. We sought to determine the survival benefit and cost effectiveness of risk-reducing mastectomy (RRM) among women with BRCA1/2 mutations following stage II–IV ovarian cancer. We constructed a decision model from a third-party payer perspective to compare annual screening with magnetic resonance imaging (MRI) and mammography to annual screening followed by RRM with reconstruction following ovarian cancer diagnosis. Survival, overall costs, and cost effectiveness were determined by decade at diagnosis using 2015 US dollars. All inputs were obtained from the literature and public databases. Monte Carlo probabilistic sensitivity analysis was performed with a $100,000 willingness-to-pay threshold. The incremental cost-effectiveness ratio (ICER) per year of life saved (YLS) for RRM increased with age and BRCA2 mutation status, with greater survival benefit demonstrated in younger patients with BRCA1 mutations. RRM delayed 5 years in 40-year-old BRCA1 mutation carriers was associated with 5 months of life gained (ICER $72,739/YLS), and in 60-year-old BRCA2 mutation carriers was associated with 0.8 months of life gained (ICER $334,906/YLS). In all scenarios, $/YLS and mastectomies per breast cancer prevented were lowest with RRM performed 5–10 years after ovarian cancer diagnosis. For most BRCA1/2 mutation carriers following ovarian cancer diagnosis, RRM performed within 5 years is not cost effective when compared with breast cancer screening. Imaging surveillance should be advocated during the first several years after ovarian cancer diagnosis, after which point the benefits of RRM can be considered based on patient age and BRCA mutation status.