Biological studies have not yet provided direct evidence for a link between electromagnetic fields (EMFs) and cancer. The hypotheses I present here describes ferritin as a direct pathway for the EMF-cancer link, which is supported by previous studies: (a) Ferritin plays a very important role in its associated cancers. (b) Iron is the principal regulator of ferritin synthesis and ferritin gene expression is induced by signals including hormones and cAMP. (c) Preliminary biological studies have demonstrated that EMFs induce some cellular effects including changes in hormone levels, alterations in cell membranes, variations of intracellular cAMP and even the modification of protein synthesis. So, it is reasonable to link the biological effects of EMFs with ferritin gene expression and ferritin synthesis which are mainly regulated by iron, hormones and cAMP and eventually the EMF-cancer link.