The article discusses winter bird populations of the waste water treatment plants (WWTP) located in the North of Left -bank Ukraine. The said population comprises 12 orders and 29 families. The most numerous are Passeriformes (37 species), Аnsеriformes (16 species) and Falconiformes (6 species). Parus major was registered at all types of facilities while most of the others house Passer montanus, Carduelis carduelis, Turdus pilaris, and Parus caeruleus. The largest number of wintering birds was registered at Bortnychi aeration station, Chernihiv municipal WWTP and Chernihiv wool processing factory - 79. 51 and 15 species respectively. The nuclear part of the bird numbers are the species residing at the facilities all year around (65.8 %); species occurring there in winter only account for 34.2 %. Dendrophilous (38 species) and hydrophilous (35 species) dominate among them. The primary role in forming the winter fauna of the waste water treatment plants belongs to the zones of water bodies and dams.