Preventive surgery is a mainstay of treatment for persons with genetic risk factors for cancer The indications of preventive surgery are based on a thorough risk assessment, clinical characteristics of the different hereditary cancer susceptibility syndromes, the types of mutation, and the possibility of watchful waiting for early cancer detection. Preventive surgery may either be recommended or represent one possible option. Bilateral prophylactic mastectomy can reduce the risk of breast cancer by up to 95% in BRCA1/BRCA2 mutation carriers. Bilateral prophylactic salpingo-oophorectomy is recommended for BRCA1/ BRCA2 carriers: women who undergo this preventive surgery have a reduced risk of ovarian cancer but also of breast cancer (around 50% for breast cancer). Patients with Lynch syndrome are at high risk of endometrial cancer, and prophylactic hysterectomy may be proposed to women for whom surgery is indicated for a uterine disorder (fibroma). Prophylactic surgery may be proposed to patients at risk of hereditary gastrointestinal malignancies, either on a case-by-case basis (Lynch syndrome) or more systematically for patients with the familial adenomatous polyposis syndrome or hereditary difuse gastric cancer Despite its efficacy, prophylactic surgery in a healthy individual, albeit at high risk of cancer, remains a difficult, multidisciplinary decision. Psychological support is needed to anticipate the possible physical psychological and social complications--and benefits.