Nanotechnology based on the use of submicronic particles of inorganic and/or organic origin has the potential to revolutionalize the clinical management of cancer; the possibility of real time monitoring of disease progression and effects of therapy is now real. Especially, iron oxide super paramagnetic nanoparticles have shown clinical utility in cancer imaging and drug delivery and some formulations are now FDA-approved for use in the clinic. The prospects of magnetic nanoparticles in cancer imaging and treatment are reviewed.