Among 1000 successive endoscopic examinations carried out in the first 6 months of 1990 in a laboratory of endoscopy 443 cases (44.3%) of sliding hiatus hernia were analysed. The examination was carried out with an Olympus GIF-Q10 fibroscope without pharmacological premedication. The diagnosis was based on the criteria described by Dagradi and Trujillo at all. In 296 cases sliding hiatus hernia was the only pathological abnormality in the endoscopic examination. In 85 cases it was associated with mucosa inflammation in the oesophagus, and in 1 case with carcinoma of the oesophagus. No correlation was found between frequency of endoscopic finding of hiatus hernia and sex and age. The analysis showed that in 110 out of 172 cases earlier routine radiological examination (63.9%) failed to demonstrate the hernia, whose direct signs were found in endoscopic examination. In no case radiological findings suggested the presence of oesophageal changes. It seems that endoscopic diagnostic of sliding hiatus hernia may contribute to explanation of the cause of "non-characteristic" gastric symptoms which in over half the cases were the cause of referral of the patients to this examination.