Investigators have used retrospective and prospective study designs to provide much needed data on the extent of risk reduction after prophylactic oophorectomy and mastectomy in women at increased risk for breast and ovarian cancer. In this publication we identify those women who may wish to consider prophylactic surgery, review data demonstrating the efficacy of prophylactic surgery, and discuss potential surgical complications. We also present data about the frequency of use and psychosocial impact of prophylactic surgery in this typically young group of women. Finally, we provide general treatment guidelines for the practicing clinician.