Natural course of gastritis is far from being clarified. Having this fact in mind we undertook this study to establish how age and sex did influence the frequency and intensity of inflammation in particular stomach portions. Possible relation between gastritis on the one hand and cholelithiasis and idiopathic non-ulcer dyspepsia on the other was also checked. The study comprised 392 persons, including 148 subjects with cholelithiasis, 130 with non-ulcer dyspepsia and 114 healthy volunteers. Endoscopy of upper digestive tract was done in all of them, the specimens of mucosa of gastric antrum and body being taken for histologic examination. Frequency of gastritis was found to rise with age, particularly up to the 40-th year of life, being analogical in both sexes. In men, gastritis showed higher intensity and activity as well as more rapid progression toward glandular atrophy. In particular age intervals no significant difference in the frequency of gastritis was found between the population of healthy persons, that suffering from cholelithiasis as well as that with non-ulcer dyspepsia.