This study was performed in different regions of Poland and the Czech Republic, using 54 hares and 30 domestic rabbits. The examined territories varied in the intensity of industrialization and agricultural production. It was found that hares were sensitive bioindicators of mercury pollution in the environment. Hg concentrations in cortical and medullar kidney parts were significantly correlated, especially in the group of older male hares. The results of Hg concentrations in the tissues of hares and domestic rabbits, from the same locations, were Compared. It was seen that not only in free-living animals but also in domestic rabbits, the mercury tissue concentration was related to environmental pollution. The Hg concentration in rabbits tissues was about 10 timer lower than that observed in hares. The highest mercury level was stated in kidneys and the lowest in muscles.The study revealed the bioindicative role of hares in the evaluation of environmental mercury pollution.