The use of mobile phones is becoming widespread with the development of technology, and as a result, its effects on human health are becoming more and more important every day. Studies have reported that the electromagnetic field (EMF) emitted by mobile phones may have adverse effects on the biological systems. In order to evaluate the effect of zinc (Zn) on C3H cancer fibroblast cells exposed to 2100 MHz EMF, we analyzed cell viability%, nuclear factor kappa b (NF-kappa B) and DNA methyltransferase (DNMT) activities. Cells were divided to following groups: Control, sham control, 2100 MHz EMF, 50 mu M Zn + 2100 MHz EMF, 100 mu M Zn + 2100 MHz EMF, and 200 mu M Zn + 2100 MHz EMF for 2 h. We measurement cell viability, NF-kappa B and DNMT activities. There was increased cell viability % in the 2100 MHz EMF group compared to the control group, while the cell viability % was decreased in the 50, 100 and 200 mu M Zn + 2100 MHz EMF groups compared to 2100 MHz EMF. NF kappa B and DNMT activities were a significant increase in the 2100 MHz EMF group compared to the control group, although were statistically decreased in the 50, 100 and 200 mu M Zn + 2100 MHz EMF groups compared to the 2100 MHz EMF group. Our results demonstrate that 2100 MHz EMF exposure in cancer fibroblast cells induce NF-kappa B and DNMT activities, whereas zinc supplementation reduce NF-kappa B and DNMT activities-induced 2100 MHz EMF.