Ultrasound is an imaging modality commonly used to evaluate breast lesions in hopes to distinguish benign from malignant solid masses. Angiogenesis, defined as the emergence of new vessels to further the growth of tumor, has stimulated interest in the potential uses of Doppler ultrasound in patients with breast cancer. This article describes different forms of Doppler ultrasound, including color Doppler (CD), power Doppler (PD), and spectral Doppler (SD), as well as 3-dimensional (3D) ultrasound and ultrasound contrast media. We review the role of Doppler ultrasound in distinguishing benign from malignant solid breast masses. We also discuss the role of ultrasound in predicting tumor grade, histology, node status, and lymphatic vascular invasion, and in monitoring breast cancer treatment.