Concerns were raised about the potential damaging effects of electromagnetic field (EMF) radiation emissions of ELF (extremely low frequency) and VLF (very low frequency) computer video display monitors (VDM), it was assessed the frequency of structural chromosome abnormalities and investigated the cell cycle kinetics in individuals occupationally exposed to VDM radiation. Chromosome aberrations were investigated in 2,000 first cell cycle metaphases obtained after 48-hour cultures of peripheral blood lymphocytes drawn from 10 individuals occupationally exposed to VDM radiation (group E) and 10 controls (group C). Cell cycle kinetics was studied using the mitotic index (MI) and cellular proliferation index (CPI). Statistical analysis showed significantly higher frequencies of anomalous metaphases (E=5.9%; C=3.7%) and anomaly/cell (E=0.066+/-0.026; C= 0.040+/-0.026) in individuals exposed to VDM radiation. The most common cytogenetic alterations seen were chromatid breaks at frequencies of 0.034+/-0.016 in group E and 0.016+/-0.015 in group C. There was no significant difference between MI and CPI frequencies in both groups. The study findings suggest genotoxic effects of EMF emissions revealed by the higher frequency of chromatid breaks in individuals exposed to VDM radiation. However, there is a need of further studies on EMF genetic effects using other investigation methods.