The objective of the study was to evaluate the prevalence of Helicobacter pylori in patients with different degrees of renal function. Two hundred and twenty consecutive patients requiring gastroscopy for upper intestinal symptoms were enrolled in the study: group I (normal renal function, n = 127), group II (chronic renal failure, creatinine clearance > 5 < 90 ml/min, n = 59), and group III (hemodialysis therapy, n = 34). On endoscopy, biopsy specimens were taken for analysis of H. pylori infection by urease test and histology. The prevalence of H. pylori in patients with renal dysfunction proved to be significantly lower than that in patients with normal renal function (22.6% vs 37%, P < 0.05). The incidence of ulcer disease in patients with normal renal function was higher than that in uremic patients (14.2% vs 10.8%, not significant). These findings indicate that uremic patients seem to be partly protected against H. pylori infection.