The problem of eutrophication of lakes in the Far North of the USSR, resulting from the input into lake systems of excess amounts of nitrogen and phosphorus, is becoming a serious one. The sources of the nitrogen and phosphorus are untreated wastes in the form of domestic sewage and wastes from meat‐packing and fish‐processing plants, since in general there is a drastic shortage of effective waste‐treatment plants. A further source in agricultural areas is the discharge of organic wastes from stock‐raising operations and of fertilizers from fields, especially on floodplains. In small lakes the phosphorus content may be 10–30 times higher than normal and the nitrogen content 7–8 times higher than normal; the dissolved oxygen content is reduced by 1.5 to 2 times, and may be reduced by as much as 2–16 times by the end of the winter. The result is a bloom of blue‐green algae and increase in the phytoplankton biomass to 17–40 times higher than usual. Zooplankton is also markedly affected. The problem also leads to a reduction in the quality of the water to the point where it no longer meets health standards. The author proposes that the capacity of treatment plants must be increased and that agricultural practices must be modified to reduce the discharge of organic matter and fertilizers into the lakes. He also suggests that a monitoring system should be put into place.