Aim. The objective of the present study was to evaluate the distribution of the focal changes over the oesophageal mucous membrane (OMM) in the patients presenting with the erosive form of gastroesophageal reflux disease (GERD) and the prevalence of the Barrett’s oesophagus (BO). The secondary objective was to estimate the diagnostic significance of confocal laser endomicroscopy (CLEM) employed to reveal neoplastic changes in OMM. Materials and methods. OMM biopsy specimens for the morphological studies were obtained from 214 patients presenting with erosive oesophagitis (EO). Thirty patients in whom the primary examination revealed the sites suggestive of hyperplasia, metaplasia or dysplasia were additionally examined with the application of such visualization techniques as NBI, ZOOM, and CLEM. A total of 46 surface focal changes were identified in OMM of the participants of the study. Results. The presence of focal changes in OMM was documented in 81 (37,9%) patients of the 214 ones. 11 (5,1%) of them presented with the combination of several types of the changes. Hyperplasia was diagnosed in 17,3% of the patients, focal gastric metaplasia in 14,6%, focal intestinal metaplasia in 5,1%, dysplasia with concomitant intestinal metaplasia in 0,9% of the patients suffering from the erosive form of GERD. The studyh as demonstrated the diagnostic value of the combination of NBI + ZOOM + CLEM: the sensitivity of combination of these methods for the detection of hyperplasia was estimated at 100%, specificity at 84%, and accuracy at 95,7%. The values of these characteristics for gastric metaplasia were 90.9, 100, and 97,8%; for intestinal metaplasia 100, 97,4, and 97,8% respectively. Conclusion. The focal changes in oesophageal mucous membrane are widespread among the patients presenting with the erosive form of GERD. Barrett’s oesophagus is diagnosed in 6% of the patients. The combination of NBI + ZOOM + CLEM is of high diagnostic value for the visualization of the changes in the oesophageal mucous membrane of the patients presenting with the erosive form of gastroesophageal reflux disease