Positron-emission tomography (PET) scan is a widely used imaging modality in the management of various malignancies. There is considerable controversy regarding its use in breast cancer diagnosis and treatment. In this review, we discuss published data on the use of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG-PET) in the staging workup of locally advanced breast cancer, and management of locally recurrent and metastatic breast cancer. FDG-PET is a useful tool in staging advanced breast cancer and assessing the extent of disease involvement when metastasis is suspected. It might also aid in assessing early response to therapy. Future goals of improving PET scan accuracy in the management of breast cancer will be achieved through utilizing radiotracers, based on a better understanding of tumor biology and improvement in breast-specific PET scans.