The effects of iron exposure, on serum iron, serum superoxide dismutase ( SOD), a free radical scavenger, and plasma malondialdehyde (MDA), a lipid peroxidation parameter, were investigated in Turkish iron miners, office workers and healthy control subjects. Serum iron levels in both miner and office workers groups were higher than those of healthy controls (p< 0.05). There were higher mean values of plasma MDA levels in both iron miners and office workers compared to controls ( p< 0.05). Serum SOD activity in the miner group was lower than that of controls ( p< 0.05). These results suggested that elevated MDA levels in both miners and office workers were the result of an increased production and/or decreased catabolism of MDA in chronic iron exposure. These changes in MDA metabolism may be due to iron-induced lipid peroxidation in the blood and related body compartments.