The paper presents data of the assessment of Ishim ecological state dynamics by the method of fluctuating asymmetry. The ecological state of the urban environment should ensure favorable living conditions for the population and a high quality of life. We assessed the degree of fluctuating asymmetry using the example of drooping birch ( Betula pendula ) leaves at 4 points of the city remote from each other (10 trees per 1 point, 100 leaves were selected from each tree). On the basis of morphometric measurements, an integral indicator was calculated, with the help of which the magnitude of asymmetry was estimated. The average values of fluctuating asymmetry of drooping birch leaves in all studied points of the city did not exceed the conditional norm. The ecological state of the city of Ishim can be assessed as favorable. In the dynamics of 11 years there was a deterioration of the ecological state of most districts in Ishim. In three observation areas, an increase in the index of fluctuating leaf asymmetry from 1,5 to 4 times was registered compared to 2010. The lowest indicators of leaf asymmetry were observed in the area of the park Berezovaya Roschya and in the area of the Prigorodny forest (Vankovka). The highest indicators of leaf asymmetry were observed in the area of the railway station. On the contrary, there was a significant improvement of the ecological state within the streets of Lunacharsky and Tolstoy in the city.