Snow cover as the accumulator of pollution of various nature draws to itself increasing attention of researchers. Chemical methods of the analysis ap-plied in environmental monitoring cannot always give complex assessment of the state of environ-ment, on which biological methods of the analysis, for example, by means of biotesting are capable. The work purpose is the assessment of the condi-tion of snow cover from the territory of green zones (squares and parks) Krasnoyarsk on dynamics of survival and mortality of test object of infusorium of Paramecium caudatum. Snow tests (integrated test from 3-4 repetition) were selected on the territory of a number of squares and parks (a track, a lawn) of Krasnoyarsk in March, 2017. For the assessment of sharp toxic impact on test object method of indi-vidual (parallel) lines of parametion was used. Ana-lysed snow samples selected from the territory of squares and parks of Krasnoyarsk on reaction of survival of protozoa are estimated in most cases as admissible (Ti = 0.0-0.21) and moderately toxic (Ti = 0.29-0.61). Considerable toxic effect was noted in the tests from the territory of the reserve "Stolby" (track) (Ti = 0.87), estimated at the level of high toxicity. Toxic effect of indicator of survival of infu-sorium of Paramecium caudatum was shown gen-erally at the level of 5-60 % and individuals‟ mortal-ity was higher. The tests from tracks were found to be more toxic in comparison with lawns. The de-crease in survival of cells of infusorium of Parame-cium caudatum in experimental tests after 60 minutes of experiment is noted. As a result of the analysis of samples of snow it is possible to allo-cate the sites estimated as the most toxic: Ener-getiki, Vavilov Street, 26 Baku Commissioners St.