The objective of the present work was to study the structure of epiphyton in water bodies significantly differing in the degree of their contamination. In the studied water bodies, the concentration of ammonia (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00706-ilm01.gif"/>) accounted for 0.04-74.00 mg/L; nitrite (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00706-ilm02.gif"/>), 0.002-1.750 mg/L; nitrate (<inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00706-ilm03.gif"/>), 0.13-58.00 mg/L; inorganic compounds of phosphorus (Pinorg), 0.041-0.272 mg/L; chloride (Cl-), 34.5-560.5 mg/L; whereas the content of organic matter (DO) was 18.0-81.0 mg O/L. The numbers of algae were determined by a direct count. Biomass was calculated by the count cell volume method. The Generic Diatom Index, the Pantle-Buck saprobic index, and the Shannon index of species diversity were used to analyze algal community structure. This study found that epiphyton responded to heavy pollution with changes in its species richness, taxonomic structure, species composition, quantitative indices, numbers and biomass structure, dominant complex, and ecological spectrum.