Background: This study was performed to evaluate the levels of heavy metals in the livers and kidneys of cattle, sheep and goats from a mining region in the west of Iran. Methods: In this cross-sectional study, 90 samples were collected from the livers and kidneys of cattle (n=30), sheep (n=30) and goats (n=30) from a slaughterhouse in Hamedan City, western Iran. Lead, cadmium, manganese, zinc, copper, and iron concentrations were analyzed using Atomic Absorption Spectroscopy. Results: Lead concentration exceeded the permissible limit in all samples. Cadmium level was within the permissible limit in most samples, except for the cattle and sheep kidneys. Iron concentration was normal in all samples, except for sheep livers and kidneys. The rest of the elements (manganese, zinc and copper) were within the safe range. There were no sex and agerelated significant differences in metal concentrations of cattle samples. The highest effects of age and sex were observed in sheep samples. Conclusion: The soil of these areas contains high level of lead and cadmium, contaminating the plants, water and animals of these regions; therefore, precise care and health inspection of livestock in these areas are recommended. Keywords: Environmental Pollution, Heavy Metals, Liver, Kidney, Ruminants
