Apart from BRCA1, BRCA2, and TP53, more than a dozen breast cancer susceptibility genes have been identified. Recognizing affected individuals depends on evaluation of cancer family history and recognition of certain phenotypic markers on physical examination. Genetic testing provides a powerful tool for individualized risk stratification. Mutation carriers have several options for managing risk, including lifestyle alterations, enhanced surveillance, chemoprevention, and prophylactic surgery. Genetic counseling and testing should be considered in the initial evaluation of patients with newly diagnosed breast cancer because this information contributes to surgical decisions, radiation therapy options, and systemic therapy choices.