The purpose of this work was to study morphological features of gastric mucosa depending on polymorphism of IL-l1beta and IL-1RN genes in children with chronic gastritis infected with different strains of Helicobacter pylori 0. We examined 106 children with HP-associated gastritis. The results suggest association of mucosal inflammation with T allele in polymorphous C-511T locus of IL-1beta (beta2 = 14,006; alpha = 0.001). agA + strains of HP were more frequently identified in patients with erosive ulcerative defects of gastric mucosa than in children with superficial gastritis (p < 0.05). The possibility of gene typing to form a group of patients with the unfavourable post-eradication clinical course for the prevention of duodenal ulcer and stomach cancer is discussed.