Aim. The objective of the present study was to evaluate the diagnostic value of esophagogastroduodenoscopy (EGDS) with the application of such visualization techniques as confocal laser endomicroscopy (CLEM), NBI, and ZOOM-endoscopy with special reference to the detection of focal lesions in the gastric mucosa. Material and methods. The study included a total of 128 patients at the age varying from 29 to 96 years presenting with the focal lesions in the gastric mucosa. All of them underwent the comprehensive endoscopic examination with the application of EGDS supplemented by CLEM, NBI, and ZOOM-endoscopy with the subsequent comparison of the endomicroscopic and histological pictures of the intact gastric mucosa and of that affected by metaplasia, hyperplasia, dysplasia, and cancer. CLEM was carried out with the use of the Cellvizio system («Mauna Kea Technologies», France). The application of the above techniques made it possible to verify 231 focal lesions of the gastric mucosa. Results. The study has demonstrated the diagnostic value of the comprehensive endoscopic examination including NBI, ZOOM, and CLEM. The sensitivity, specificity, and precision of these methods for the detection of intestinal metaplasia was estimated at 100%, 91.1%, and 99.1% respectively. The same characteristics for the detection of mucosal hyperplasia were 44.1%, 100%, and 91.8% respectively and for the detection of earlier cancer 100%, 95.4%, and 96.1%. Conclusion. The combination of the modern endoscopic updating techniques including esophagogastroduodenoscopy supplemented by NBI and ZOOM-endoscopy and confocal laser endomicroscopy (CLEM) is needed to detect and verify superficial epithelial structures in the stomach. Such combined approach is characterized by high diagnostic sensitivity, specificity, and precision that allow to detect and evaluate changes in vivo in real time at the cellular level without damaging the tissue structure. The use of the endoscopic technique together with CLEM significantly enhances the diagnostic value of targeted biopsies.