To determine the importance of gastrointestinal evaluation in pretransplantation phase in pediatrics with End Stage Renal Disease (ESRD). Twenty four children with ESRD (13 female, 11 male) mean age 14.7 (±3.4) years on maintenance hemodialysis were included in this study. Upper gastrointestinal endoscopies were performed and four gastric antral and duodenal biopsy specimens were obtained for urease test and histological study for all patients. Serum gastrin levels were measured in all patients, too. A control group was chosen to compare the rate of H. pylori infection using student’s t. test. Gastrointestinal symptoms were present in 16 (67%) of 24 patients. Seventeen (71%) patients had abnormal upper gastrointestinal endoscopic findings. H. pylori was detected in 66% of patients and 20% in control group (p<0.001). In symptomatic patients 75% had abnormal endoscopic findings and 63% had positive urease test for H. pylori infection. While, in asymptomatic cases these rates were 30% and 75%, respectively. Seventy one percent of patients with gastrointestinal lesions and 50% of patients with normal endoscopic examination were infected. High serum gastrin levels in infected and non-infected patients were detected in 75% and 12.5%, respectively (p<0.001). We demonstrated a significant number of patients with peptic ulcer diseases and H. pylori infection and secondary hypergastrinemia. This study showed that, clinical symptoms are not a reliable predictor of gastrointestinal problems. Our results emphasize the importance of periodic, and also pre-transplant gastrointestinal evaluation in these patients to find out their problem and manage appropriately.