We assessed gastric myoelectric functioning in patients with various gastrointestinal symptoms and to determine the utility of electrogastrography in differentiating specific disease entities. Electrogastrography with a water load was performed in 101 patients with reflux disease, 55 patients with active gastric ulcer, 59 patients with functional dyspepsia, and 30 controls. Upper gastrointestinal symptoms were assessed in each patient. Electrogastrography was abnormal in 41 (40.6%) patients with reflux disease, 31 (56.4%) patients with active gastric ulcer, and 26 (44.1%) patients with functional dyspepsia (P=NS). Water load tolerance was greater in controls than any patient group (all P<0.05). Symptoms predicted abnormal electrogastrography in reflux patents with satiety (OR=2.9; P<0.05) and in dyspeptic patients with nausea (OR=3.1; P<0.05). Although electrogastrography is helpful in differentiating subgroups of patients with nausea or satiety, it cannot directly differentiate disease states such as reflux disease, gastric ulcer, and functional dyspepsia.