BACKGROUND: Helicobacter pylori infection and the resulting inflammation of the stomach are widely recognized as the primary risk factors for the development of gastric cancer (human health). Despite numerous attempts, the correlation between various virulence factors of H. pylori and stomach cancer remains mainly unexplained. The cag pathogenicity island (cagPAI) is a widely recognized indicator of virulence in H. pylori. MicroRNAs play crucial roles in a wide range of biological and pathological processes and dysregulated expressions of miRNAs have been detected in numerous cancer types. However, research on the correlation between H. pylori infection and its cagPAI, as well as the differential expression of microRNAs in gastric cancer, is lacking. AIM: The aim of this study was to examine the differential expression of miRNAs in 80 patients with gastric cancer, specifically in connection to the presence of H. pylori and its cag pathogenicity island (cagPAI). METHODS: Biopsies of 80 gastric cancer patients were collected and used for H. pylori DNA isolation and tissue miRNA isolation, and further analyzed for cagPAI and miRNA expression and their association. RESULTS: Elevated levels of miR-21, miR-155, and miR-223 were detected in malignant tissues. The expression of miR-21 and miR-223 was considerably elevated in biopsies that tested positive for H. pylori, whereas the expression of miR-34a was reduced. H. pylori cagPAI samples that are functionally intact exhibit greater expression of miR-21 and miR-223 compared to cagPAI samples that are partially deleted, in both normal and malignant tissues. CONCLUSION: Thus, the novelty of our study lies in its focus on the differential expression of specific miRNAs in relation to the functional integrity of the cagPAI in H. pylori-infected gastric cancer patients, offering a more detailed understanding of the interplay between H. pylori virulence factors and miRNA regulation than previous studies.