Prion diseases are rare neurodegenerative diseases but have gained considerable notoriety because of BSE and its links to the human disease, variant CJD. However, prion diseases, like other amyloidogenic diseases, are linked to changes to a key protein. The prion protein's change in conformation is considered the pivotal event that leads to prion disease. However, this mysterious protein has been hard to understand in terms of its role in the cell and the events that trigger this conformational change. One of the key findings that have changed the way we view these diseases is discovery of the ability of the prion protein to bind metals. In particular the normal isoform of the prion protein binds copper. Expression of the prion protein by cells has also been shown to protect cells, particularly from oxidative damage. Binding of the "wrong" metal, manganese plays a role in protein conversion. Therefore the study of metals in prion disease has proven a very rich ground for understanding these complex diseases and the enigmatic protein associated with them, the prion protein. This chapter provides an up-do-date review of the current knowledge of the prion protein as a metalloprotein.