In the study the nature of change of fluctuating asymmetry of signs of leaf plates of Manchurian nut and birches in the conditions of polluted atmospher-ic air of the city of Krasnoyarsk is considered. The assessment of stability of development of the birch on the fluctuating asymmetry of a leaf plate was carried out by many researchers, and comparative assessment of stability of development of intro-duced species, i.e. Manchurian nut in the condi-tions of the city of Krasnoyarsk was carried out for the first time. As materials for herbarium research leaf plates of birch and Manchurian nut, selected in 2015 and 2016 in the territory of Sverdlovsk district of Krasnoyarsk served. The processing of received results was made using traditional and basic way of statistical data normalization. It was established that studied plants had been growing in the condi-tions of rather strong anthropogenous pollution as have essential violations in the development ac-cording to the modified scale of D.B's Gelashvili and I.D. Mokrov. So, the birch matters integrated fluctuating asymmetry: traditional - 0.056, rated - 0.046 (2015), Manchurian nut: traditional - 0.094, rated - 0.121 (2015). It was revealed that at leaf plate of the birch the asymmetry of the distance between the bases of the first and second veins of the second order, and at a leaf plate of Manchurian nut was asymmetry of the distance between the bases of the first and second veins of the second order, the distances between the ends of the first and second veins of the second order, the corner between the main vein and the second from the leaf basis, the vein of the second order was most expressed. Natural violation of development stabil-ity of a leaf plate of Manchurian nut during vegeta-tive period was shown. Thus, it is necessary to conduct systematical researches in this direction for the establishment of regional scale of the assess-ment of development stability of introduced species in the conditions of large industrial city (Krasno-yarsk).