Background. Helicobacter pylori (H. pylori) is considered to cause gastritis and gastric ulcer. In dialysis patients, digestive tract hemorrhage is sometimes fatal. However, in regard to H. pylori infection in patients with end-stage renal disease (ESRD), many issues remain to be clarified. Methods: This study included 76 symptom-free patients with ESRD. The subjects consisted of 25 patients with chronic renal failure who had not received dialysis and 51 patients receiving dialysis. On upper digestive tract endoscopy, specimens were taken for analysis of H. pylori. Urease test, culture, and microscopy were performed. Results: In non-dialysed patients, the prevalence of H. pylori-positive patients was 56.0%. In dialysed patients, the percentage was significantly lower (27.5%). In dialysed patients, the mean duration of dialysis was 8.1 +/- 7.5 months (mean +/- SD) in H. pylori-positive patients and 56.2 +/- 60.9 months (mean +/- SD) in H. pylori-negative patients (p < 0.001). 11 of 13 non-dialysed patients with chronic gastritis were positive for H. pylori. However, only 5 of 24 dialysed patients were positive for H. pylori infection. Conclusions: Long-term dialysis decreased the prevalence of H. pylori. The reduction of gastric acid secretion related to chronic gastritis may be involved. Copyright (C) 2002 S. Karger AG, Basel.