The article dedicated to the problem of the diagnostic value of morphological changes in gastroesophageal reflux disease in the biopsy of the distal esophagus in pubertal children of childbearing age.Aim of the research is to investigate the diagnostic value of morphological changes in gastroesophageal reflux disease in esophageal biopsy material in adolescents sickly with acute respiratory diseases.Methodology. The objective of the study was achieved through examination of 90 adolescents (10 to 16 years old, average age 13.1±3.54 years) kept under observation at the Children's Clinical Hospital No. 9 of Kyiv and on the basis of the Department of Pediatrics No. 1 Center of Primary Health Care No. 4 of the Desnianskyi district of Kyiv. All adolescents belonged to the group of sickly with a number of respiratory diseases averaging 6-8 times a year, lasting from 8 to 18 days (on average 12.8±5.41 days). All children have undergone endoscopic examination of the esophagus, stomach and duodenum with the esophagus mucosa biopsy using the OLYMPUS GIF-P3 flexible fiberscope.Results. It was found that the least valuable diagnostic feature in the morphological examination of the mucous membrane of the distal esophagus in the pain-causing children with GERD was thickening of the epithelium with a sensitivity of 13,0 %, a specificity of 96.0 %, and total value of 65.0 %. It has been proved that hyperplasia of cells of the basal layer of the mucous membrane of the distal esophagus at the GERD in the infected children is 46.7 % (specificity – 93.3 %, the total value is 75.6 %). Increase in the number of papillae and their prolongation in 33.3 % cases (sensitivity – 33.3 %, specificity – 93.3 %, overall diagnostic value – 70.8 %).Conclusion. The peculiarity of the morphological manifestations of GERD in childbearing children is dystrophic changes in keratocytes in the superficial parts of the multilayer squamous epithelium, which are detected at 100.0 % of patients (specificity is 93.3 %, total value is 96.8 %), with parakeratosis centers at 13.3 % of cases. It has been shown that a frequent and diagnostically valuable indication is inflammatory infiltration of the esophageal mucosa, which are verified in all cases (100.0 %, with dilatation and hyperemia in 46.7 % of patients (specificity – 40.0 %, total value – 81.3 %).