It is for the first time in Ukraine that a study has been made on the epidemiology of H. pylori infection among patients with disorders of the stomach and duodenum. The diagnosis of the infection was done with the aid of various invasive and noninvasive tests, 13C-urea breathing test, a unique for Ukraine and countries of the Western Europe method of examination included. Ascertained among the above category of patients was wide prevalence of H. pylori, which fact confirms its leading etiological role in disorders of the stomach and duodenum once again.