The authors analyze the results of bacteriologic studies carried out in patients with intestinal infections at the laboratory of the Sanitary Epidemiologic Center of the town of Irkutsk over 1984-1988. The records of 24,490 case histories show infections induced by opportunistic microflora in 37 percent of cases. The most frequent etiologic agents were Staphylococcus aureus and Enterobacteriaceae, genera: Proteus, Enterobacter, Citrobacter, Klebsiella, Hafnia. Analysis of the incidence of acute intestinal infections induced by opportunistic bacteria in various age groups evidence that mostly infants aged under 1 suffer from them. In older children S. aureus is no longer etiologically significant and it is replaced by Enterobacter and Klebsiella. The authors find it interesting to compare the etiological patterns of enteritis induced by opportunistic microorganisms in various regions of our country.