Purpose: to investigate the frequency of release of causally significant microorganisms in diarrheal disorders for children in different age groups, who live in environmentally unfavorable conditions in the Donetsk region (Kramatorsk). Material and research methods. The results of bacteriological studies of the intestinal microflora were provided by the Children’s Infectious Diseases Department of the CNE «Children’s Territorial Medical Association» Kramatorsk City Council from 2016 to 2018. The microbiological research of the intestinal microflora of 2565 hospitalized children, aged 1 to 16 years, in the Donetsk region with diarrheal disorders of varying severity, was conducted. Results. Enterobacter cloacae is the most common microorganism among sick children during the study period: 36.7±0.30% in 2016, 42.8±0.30% in 2017 and 20.4±0.30% in 2018, Klebsiella pneumoniae is the second: 26.8±0.38; 30.9±0.38 and 42.3±0.38%, respectively. Conclusions. The research demonstrated that Enterobacter cloacae and Klebsiella pneumoniae, that are opportunistic pathogens, are significantly superior to other bacteria and increase the evence of diarrheal disorders in children (mainly at the age of 1 to 3 years), that should be explained by the lack of hygienic skills in children of this age group.