It is believed that extreme low frequency magnetic fields (ELF-MF) are not mutagenic, at least at exposure levels below 100 μT. Synergistic or co-operative effects with environmental mutagens remain possible yet. We therefore investigated the effects of ELF-MF in conjunction with 4 different well known chemical mutagens having different modes of action. For this purpose the bacterial Vitotox test was used. Our study confirmed previous results which showed that a 100 μT magnetic field (50 Hz) does not damage DNA and hence is not mutagenic in this assay and that there was also no influence on the DNA damaging capacity of the used mutagens.