Nanoparticles are being actively developed for biomolecular profiling of cancer biomarkers, tumor imaging in vivo, and targeted drug delivery. These nanotechnology-based techniques can be applied widely in the management of different malignant diseases, such as breast cancer. Although the number of different types of nanoparticles is increasing rapidly, most can be classified into two major types: particles that contain organic molecules as a major building material (such as dendrimers, micelles, liposomes and carbon nanotubes, and other polymers); and those that use inorganic elements, usually metals, as a core. In particular, inorganic nanoparticles have received increased attention in the recent past as potential diagnostic and therapeutic systems in the field of oncology. This review primarily discusses progress in applications of inorganic nanoparticles for breast cancer imaging and treatment.