Background/Aims:The prevalence of gastroesophageal reflux disease (GERD) in chronic renal failure patients and in renal transplant recipients (RTR) has been a subject of discussion in the last few years. Our aims are to clarify this association and its relation to Helicobacter pylori infection, and also to identify possible pathogenic factors in the development of this disease in both groups.Methods:The study involved 40 end-stage renal disease (ESRD) patients with upper gastrointestinal (GI) symptoms (group I), 36 patients who had undergone kidney transplantation and had similar symptoms (group II), and 44 age- and sex-matched controls with the same upper GI symptoms (group III). All patients were subjected to esophagogastroduodenoscopy, and biopsies were obtained from the antrum for histological evaluation and identification of H. pylori.Results:The prevalence of GERD in the first two groups was similar (77.5 vs. 75.0%, P = 0.412), while it was significantly lower in the control group (38.6%, P < 0.01). H. pylori infection was present in 40.0, 36.1 (P > 0.05) and 75% (P < 0.01 and < 0.001) of the patients in groups I, II, and III, respectively. Multivariate logistic regression analysis in groups I and II showed that high serum creatinine (Odds ratio [OR] = 6.78, 95% Confidence Interval (CI) = 1.12-45.82), immunosuppressive therapy (OR = 5.78, 95% CI = 1.01-32.5), and absence of H. pylori infection (OR = 3.58, 94% CI = 1.11-18.6) were significantly associated with GERD. The duration of ESRD correlated significantly with the prevalence of GERD in group I.Conclusions:This study showed a similar prevalence of H. pylori infection and GERD in ESRD and RTR patients. GERD prevalence was higher in these two groups than in the controls. Renal transplantation, chronic renal disease, immunosuppressive therapy, and the absence of H. pylori infection seem to be risk factors for the development of GERD.