Zinc is essential for cells and intracellular zinc levels are maintained within appropriate boundaries by zinc transporters. However, increasingly, changes in intracellular zinc have been observed in a number of different cancers. Furthermore, these changes in zinc levels are often accompanied by parallel alterations in the expression of different zinc transporters. In this chapter we will detail what is known about zinc and zinc transporter levels in different cancers with particular emphasis on breast cancer, which has been examined most thoroughly. It is hoped that what has been discovered regarding the involvement of zinc and zinc transporters in breast cancer will be applicable to future investigations of other cancers.