Upper gastrointestinal discomforts are common in uremic patients. Investigators have stressed the structural, histopathological, and physiological changes in the gastrointestinal tract in the past decades. Few data are available about the electrophysiological changes in the stomach of uremic patients. It is not known whether hemodialysis alters gastric myoelectrical activity. More interestingly, what is the long-term effect? To address these questions, we measured gastric myoelectrical activity before and after hemodialysis in patients with end-stage renal disease on maintenance dialysis treatment. Twenty-one uremic patients with dyspeptic complaints were enrolled in this study. Gastric myoelectrical activity was measured noninvasively using abdominal surface electrodes (electrogastrography). The paired variables obtained before and after hemodialysis were compared statistically. We also compared the difference between two subgroups defined as new hemodialysis patients and chronic hemodialysis patients. We found that there was a significantly lower percentage of normal slow-wave frequency obtained after hemodialysis in comparison with before hemodialysis (fasting state: 49.1 +/- 4.8% vs 68.1 +/- 5.4%, P < 0.01; fed state: 53.8 +/- 6.9% vs 73.4 +/- 4.1%, P < 0.01). In comparing the subgroups, there were no differences between each EGG variable. We concluded that the hemodialysis itself compromised gastric myoelectrical activity in its immediate effect. However, there were no permanent effects regarding gastric myoelectrical activity itself.