Patients with breast cancer use complementary and alternative medicine (CAM) despite the fact that no studies have shown altered disease progression attributable to CAM use. The purpose of this systematic review is to summarize research as it relates to CAM use among women with breast cancer. Among the many findings of the review, biologically based practices were noted as the types of CAM most used by women with breast cancer, followed by mind-body medicine, whole medical systems, and energy medicine. Sources of information about CAM use for women with breast cancer vary widely, including family, friends, mass media, healthcare providers, CAM providers, and self-help groups. Sociodemographic factors that appear to be related to CAM use were younger age, higher education, higher income, married status, involvement in a support group, and health insurance. The reasons for CAM use reported by women with breast cancer were to help healing, to promote emotional health, and to cure cancer. Oncology nurses should learn more about CAM use among women with breast cancer. Open communication about CAM use helps ensure that safe and holistic care is provided. Additional research in this particular area is needed.