Objective: Modern people are exposed to many environmental factors, including Extremely Low-Frequency Magnetic Fields (ELF-MF). ELF-MFs are emitted from everything that produces electricity or that it passes through. Some studies have shown no significant detrimental effect of ELF-MFs on biological systems, while other studies have shown that ELF-MFs increase the risk of the development of childhood leukaemia (1). Moreover, the 40 Hz-7mT range ELF-MF has been used as a magnetotherapy instrument (2). In this study, we aimed to compare the effect of ELFMF on healthy dermal fibroblasts and breast cancer cells (MCF7).