Vascular abnormalities of the breast include a wide spectrum of arterial and venous disorders, as well as benign and malignant vascular masses. Multimodality imaging is often necessary to accurately diagnose several of these uncommon conditions, and pathologic correlation can be important for accurate diagnosis of vascular masses. After a review of the vascular anatomy of the breast, the authors discuss the imaging appearance of several native arterial disorders (atherosclerosis and aneurysm) and venous disorders (superior vena cava syndrome, congestive heart failure, thrombophlebitis, and varix). Benign vascular tumors (hemangioma, lymphangioma, and angiolipoma) and malignant vascular tumors (angiosarcoma and hemangiopericytoma) that may be encountered in the breast are also reviewed. In addition, pitfalls in the correct interpretation of vascular breast lesions (devascularization of masses and pathologic mimics) are reviewed. Understanding and assessing normal and pathologic breast vasculature will permit more accurate diagnosis and treatment planning and allow breast imagers to have a more active role in breast care.