In order to determine the effects of environmental contamination, nuclear abnormalities of peripheral erythrocytes and lung, liver, and kidney histopathologies were evaluated in marsh frog (Pelophylax ridibundus) in agricultural areas. The most prominent histopathological alterations observed in lung tissue were noted as epithelial hwerplasia. thickness of alveolar septa, dilatations and congestions of blood capillaries, and melanomacrophage accumulation. An increase in the number and widening of melanomacrophage centers were also noted for liver, in parallel with hepatocyte degeneration and heterogenic vascular construction originating from congestion, deformation and dilatation. In kidney, degeneration, congestion, dilatation, and necrosis in proximal and distal tubules were recorded.. moreover, expansions of Bowman's space, infiltrations of lymphocytes, and glomertdonephritis were observed. Also, the frequency of nuclear abnormalities in erythrocytes showed significant differences between the sites. Quantitative analyzes of histopathological and nuclear alterations indicated that the highest effects of pollutants in frogs were at the agricultural sites in June.