Mutual effects of microbial complexes of biological objects, men and their environment are of crucial importance for manned space missions. The present experiment to study wheat microflora flown in a manned spacecraft was a continuation of investigations the purpose of which was to identify the pattern of formation of microbial cenosis of higher plants in a closed ecological system. It was found that the microbial cenosis of plants grown during an early period of vegetation in space was formed under the influence of the anthropogenic factor. It was characterized by a high bacterial and fungal concentration of their phyllosphere and, to a lesser extent rhizosphere, occurrence of Escherichia coli representatives, and increased amount of cellulose-lytic bacteria.