The role of microorganisms in destructive processes occurring in concrete and reinforced concrete structures is considered. The mechanisms of microbiological effects on concrete surfaces and in the formation of microbial biofilms, are described. The main groups of corrosive microorganisms — in particular sulfur-oxidizing and sulfate-reducing microorganisms—are characterized. The principal methods for analyzing the processes of microbiological corrosion and protection of concrete from biological destruction are adduced.