This study evaluates the effects of electromagnetic fields (EMF) on the rat glioma cell line C6. For periods up to 14 days, cells were exposed to 2 mT, 60 Hz, sinusoidal EMF for 6 h per day. We examined whether exposure alters proliferation, differentiation, cell cycle distribution, or actin distribution of the C6. When the initial seeding density was 103 cells per 9.6 cm2 growth areas, EMF accelerated the proliferation of C6. When the initial seeding density was 104 cells per 9.6 cm2 growth areas, however, EMF inhibited cell growth. On the other hand, there was no correlation between EMF exposure and cell differentiation. The flow cytometric analysis shows that, when the initial seeding density was 104 cells per 9.6 cm2 growth areas, the proliferation potential of EMF-treated cells was higher than that of control cells on 14 days of culture. Regardless of the initial cell seeding, EMF induced the cytoskeletal modification of cells. In conclusion, the observations in this paper support that EMF may modify structure and function of glioma cell.