Women who have been treated for a childhood, adolescent, or young adult cancer are at an increased risk for developing breast cancer at a young age, and breast cancer accounts for the most common subsequent malignant neoplasm among female childhood and adolescent cancer survivors. Risk of breast cancer in these survivors appears to be a multifaceted relationship between constitutional factors, exposures to radiation therapy (RT) and chemotherapy, and genetic predisposition. Given the significant morbidities and mortality associated with a breast cancer diagnosis, it is imperative that health care providers understand the risks, biology and genetics, recommended surveillance guidelines for early detection, and potential prevention strategies for women who have survived pediatric and young adult cancer.