Selenium is an essential trace element while having a potential toxicity. It can be identified and measured in urine, milk and and hair. Samples of serum and hair from six dairy farms at different radius around ceramic industries of Isfahan (0.1, 1.5 and 2.5 km, 2 farms in each zone and 24 cattle in each distance) were randomly taken. Samples (serum and hair) were also taken from 2 farms, 15 km away from the polluting sources, as control group. The concentration of selenium in serum and hair samples were measured against certified standard solutions by atomic absorption spectrophotometry. The results revealed that the mean selenium concentration of hair, at the radius of 0.1 km from ceramic industries, was significantly higher than control group (P<0.05). This concentration was significantly lower than the concentration of hair selenium at the radius of 1.5 km from the ceramic industries. The selenium concentration of hair and serum at the radius of 1.5 km was higher than those of other distances (P<0.05). The results of selenium measurements in the region showed a possible presence of subclinical selenium deficiency. Meanwhile, it could be concluded that the level of pollution have not been at a level that can cause poisoning, rather a compensation of this trace element occurred in the area, which was not still able to maintain normal selenium concentration. It seems that the higher concentration of selenium at the radius of 1.5 km may be due to the pattern of precipitation of pollutants around the ceramic industries. It was concluded that the presence of ceramic industries in the region partially compensated the low concentration of selenium in the region which was not still enough to compensate the deficiency. Furthermore, the findings of this study, revealed the potential use of hair selenium as indicator of body status of this trace element.