In this article, we review the history of testing for mutations in breast cancer susceptibility genes and discuss the current state of testing for mutations in BRCA1 and BRCA2 in different clinical settings including at-risk individuals and cancer patients. The risk of breast cancer. other associated malignancies and prognosis in carriers of these mutations are reviewed. A final section includes discussion of current recommendations for surveillance and the need for further research to identify environmental and genetic factors which modify the risk of developing cancer in mutation carriers.