To explore the potential contributions of gastroesophageal reflux disease, as opposed to Helicobacter pylori infection, to the development of gastric carditis, we evaluated gastric carditis (using the criteria of the updated Sydney system for the classification of gastritis), clinical and morphologic features of esophagitis, and H. pylori infection (evaluation of Steiner stains) in biopsy specimens from the gastroesophageal squamocolumnar junction. We correlated clinical, endoscopic, and histologic features in an unselected group of 116 patients. Some degree of carditis was found in 107 (92%) of the patients. The mean age of the patients increased with increasing severity of carditis (P < .05). The various groups of patients with different degrees of carditis did not differ significantly in sex ratio, ethnic background, presence of obesity, percentage having symptoms of gastroesophageal reflux disease (such as heartburn, regurgitation, dysphagia, or odynophagia), endoscopic evidence of esophagitis and columnar epithelium in the distal esophagus, or histologic evidence of active esophagitis. The presence, however, of active gastritis and H. pylori infection in the distal stomach and/or in the cardia was significantly associated with carditis. In patients without carditis, H. pylori was not detected in any cardiac or distal gastric biopsy specimen. In contrast, H. pylori was demonstrated in gastric tissue samples (either from the cardia or distally) of patients with carditis, with the prevalence rate increasing with greater degrees of cardiac inflammation. The H. pylori prevalence rate was 12% in the group with mild carditis, 40% in those with moderate carditis, and 57% in patients with marked carditis (P = .0001). In summary, carditis is commonly found in patients with symptoms related to upper gastrointestinal diseases. From analysis of our study cohort, we concluded that carditis was significantly associated with H. pylori infection and active gastritis but not with symptoms or signs of gastroesophageal reflux disease. These findings suggest that carditis with histologic features similar to those of gastritis in the distal stomach was a sequel of H. pylori infection and represented a part of an H. pylori--associated gastric inflammation.