The object of research is a microbiological contamination of reinforced concrete structures of the poultry house. Method. The species composition of microorganisms settled on the selected samples of reinforced concrete structures was determined in laboratory conditions. The identification of microscopic fungi was carried out according to their morphological and cultural characteristics using determinants: K. B. Raper, C. A. Thorn, 1949; K.B. Raper, D.I. Fennel, 1965; N.P. Podopilchenko (1971); M.A. Litvinov (1967); A.A. Milko (1974); Т.С. Кириленко (1977); K. Donch, V. Gams, 1980; A.U. Lugauskas, A.N. Mikulskene, D.U. Shlyauzhene (1987); V.I. Bilay, E.Z. Koval (1988). Results. Biodegradation processes in buildings with different service lives are considered. Biodegraders that affect biodegradation of concrete and reinforced concrete structures have been identified.