In children with chronic gastritis/gastroduodenitis (CG/CGD), ulcerative and erosive processes of mucous and associated allergic diseases IgM, IgA, IgG, and IgE to the H. pylori were determined by ELISA in the blood serum. IgM-antibodies to H. pylori were found in isolated cases and did not present a diagnostic significance. IgG-antibodies were detected in all children in the same percentage (40-50%), pointing indirectly to the widespread contamination by H. pylori. IgA-antibodies to H. pylori with high frequency (83% and 57%) were found in the blood serum of children with the diseases of gastroduodenal zone without allergies, while in children with allergic pathology they were found by 3-4 times less (20%). IgE antibodies to H. pylori were determined in a high percentage of cases in healthy children (86%) and allergic children (75%), while children without allergy IgE antibodies were detected in the 54-65% of cases. In this study, the detection of IgE antibodies to H. pylori has allowed to increase the frequency of the diagnosis of helicobacteriosis cases in children with gastropathology by 16% in general and in the group of children with allergic diseases this increase amounted to 27.3%. Moreover, children with antihelicobacterial IgE antibodies in a large percentage of cases (92-94%) revealed a positive urease activity. Detection of serum IgE-antibodies to H. pylori in combination with other antibodies isotypes in children increases the diagnostic significance of determination of H. pylori infection and may be recommended when applying serodiagnosis H. pylori in children's practice, especially in children with allergic pathology.