Women with increased risk of breast cancer have the treatment options of chemoprevention, surveillance or prophylactic mastectomy (PM). This article will focus on PM. PM should only be undergone after a detailed risk assessment and consultation with the patient's entire medical team, including a psychologist. PM will either be bilateral or contralateral. Bilateral PM is usually recommended to women who have a genetic predisposition for breast cancer. Research has shown that PM was 98.6% effective in preventing breast cancer in BRCA1 or BRCA2 mutation carriers. Contralateral PM (CPM) is a treatment option not often recommended to women who are being treated for breast cancer. While research has shown that CPM can offer a 95% risk reduction to contralateral breast cancer recurrence, the low risk of developing a contralateral breast cancer in the first place (0.6%) means that CPM would actually offer little benefit to most patients. However, it should be noted that the efficacy of PM for patients with invasive lobular carcinoma is controversial and further research is needed. The optimal surgical technique for removing the most breast tissue is total mastectomy, while new techniques of ‘skin sparing’ mastectomy will allow a better cosmetic outcome following reconstruction.