Breast cancer is the most common cancer in women in the United States; this year, approximately 215,900 new cases will be diagnosed. Mammography remains the cornerstone of screening, with technologies such as ultrasonography and magnetic resonance imaging having an increasingly defined role. Improved risk assessment and prevention strategies have been implemented, and current research in these areas includes better identification of patients at risk, the use of aromatase inhibitors and other agents to reduce risk, and the use of surrogate markers. Breast cancer staging has been optimized recently; also, local management of breast cancer, adjuvant systemic therapies, and treatment of patients with advanced disease have been evolving. Advances in screening, diagnosis, and treatment of breast cancer continue to influence our approach to patients with this disease. Many improvements have been made as well in supportive care, including increased tolerability of therapy and notable amelioration of disease symptoms.