The authors examined the morbidity rate of mycotic diseases of stomach and esophagus. There were 746 biopsian and abrasian cytologic samplings carried out in a year and 12.3% of the cases turned out to be positive. Comparing the two sampling patterns the abrasian cytology has proved to be more effective. The prevalence of candidiasis was found to be higher in case of malignant diseases. In states accompanied by low acid values (as in case of patients under H2-receptor blocking--treatment) mycotic infection proved to be more frequent, too.