Genetic counseling and testing for inherited disorders are part of every obstetrician-gynecologist's practice. Family history, ethnicity, and race are routinely evaluated as a part of the prenatal assessment. The discovery of genes responsible for inherited cancer susceptibility and the wide availability of clinical genetic testing for mutations in these genes have made similar assessments an integral part of gynecologic practice as well. The indications for genetic testing for mutations in BRCA1, BRCA2, and the mismatch repair genes responsible for the hereditary nonpolyposis colon cancer (HNPCC) syndrome need to be individualized. As in obstetrics, genetic counseling can provide critical assessment of the family history to help determine the likelihood of an inherited cancer susceptibility syndrome and the appropriateness of genetic testing. The subsequent clinical recommendations for mutation carriers need to take into account the patient's age, desire for future childbearing, and other medical history when prescribing screening interventions or prophylactic surgery. Practical applications of genetic testing for cancer susceptibility have the ability to reduce the burden of hereditary cancers by saving lives, decreasing medical morbidities, and reducing psychological stress.