Lynch syndrome (LS) is caused by a germline mutations in DNA mismatch repair genes and is a dominantly inherited syndrome, responsible for 2-5% of all colorectal cancer (CRC) cases. Mutation carriers have a 60-85% risk of developing CRC. With the increasing use of genetic predisposition testing, patients and health care providers must decide on cancer risk-reduction strategies. The cancers observed in families with LS are diagnosed at an unusually early age and may be multiple. The decision about which surgery is suitable should be made on the basis of patient factors and preferences, with special emphasis on age, comorbidity, sphincteric function, and the ability of the patient to cope with intensive surveillance. Colectomy decreases the risk of second CRC significantly. The estimated lifetime risk for endometrial adenocarcinoma is 40-60% in women with LS, and the mean age at diagnosis is around 50 years. This risk equals or exceeds the risk of CRC. The optimal management of the elevated risk for cancer in carriers of mutations for hereditary nonpolyposis colorectal cancer is unclear. Patients who are gene mutation carriers should receive counseling about colectomy, and if women, prophylactic hysterectomy and bilateral oophorectomy.