Qualitative and quantitative composition of gastric microflora has been studied in 30 children with chronic gastritis. Bacteriological study of gastric biopsies and parietal mucus in 10 children with chronic gastritis not associated with Helicobacter pylori more frequently revealed conditionally pathogenic bacteria--Escherichia coli, Staphylococcus aureus, Streptococcus viridans, S. pyogenes (group A), Peptostreptococcus anaerobius, P. prevotii and their associations. In 20 studied patients with H.pylori-associated chronic gastritis composition of local microflora was less diverse--conditionally pathogenic, lacto- and bifidobacteria often were absent. Study showed that eradication of H. pylori led to appearance of conditionally pathogenic bacteria in stomach microflora, which were frequently isolated in associations. Not effective treatment was associated with disappearance of lacto- and bifidobacteria and frequent isolation of Candida albicans.