This article is focused on the peculiar features of the ENT microbial paysage in the patients presenting with diabetes mellitus. We have examined a total of 310 patients including 145 suffering from the pyoinflammatory ENT diseases and concomitant diabetes mellitus. The study has demonstrated that the microbial biocenoses of the ENT organs in the diabetic patients are dominated by the potentially pathogenic and transitory microflora whereas the saccharolytic microflora and the non-fermentative bacteria (pseudomonades) concentrate in the foci of ENT inflammation. The spectrum of microorganism that occur in the areas of inflammation are shown to depend on the quality of compensation of diabetes mellitus.