Extremely low frequency electro magnetic fields (EMFs) have been classified as possibly carcinogenic tohumans by the International Agency for Research on Cancer. An increased number of chromosomal alterationsin peripheral lymphocytes are correlated with elevated incidence of cancer. The aim of the present study wasto assess occupationally induced chromosomal damage in EMF workers exposed to low levels of radiation.We used conventional metaphase chromosome aberration (CA) analysis and the micronucleus (MN) assay asbiological indicators of non ionizing radiation exposure. In the present study totally 70 subjects were selectedincluding 50 exposed and 20 controls. Informed written consent was obtained from all participants and the studywas performed in accordance with the Declaration of Helsinki and the approval of the local ethical committee.A higher degree of CA and MN was observed in exposed subjects compared to controls, the frequency of CAbeing significantly enhanced with long years of exposure (P<0.05). Moreover increase in CA and MN with agewas noted in both exposed subjects and controls, but was significantly greater in the former. The results of thisstudy demonstrated that a significant induction of cytogenetic damage in peripheral lymphocytes of workersoccupationally exposed to EMFs in electric transformer and distribution stations. In conclusion, our findingssuggest that EMFs possess genotoxic capability, as measured by CA and MN assays; CA analysis appeared moresensitive than other cytogenetic end-points. It can be concluded that chronic occupational exposure to EMFsmay lead to an increased risk of genetic damage among electrical workers.