Background/Aims: Helicobacter pylori (H. pylori) infection highly correlates with erythematous/exudative gastritis, which is one of the endoscopic findings of the Sydney classification system. The present study aimed to evaluate the association between endoscopic severity of erythematous/exudative gastritis and H. pylori infection. Methods: We prospectively enrolled asymptomatic adults who were diagnosed with erythematous/exudative gastritis during screening esophagogastroduodenoscopy. A rapid urease test was performed in all participants to diagnose H. pylori infection. The severity of erythematous/exudative gastritis was determined based on the Sydney classification system. Two investigators independently evaluated the endoscopic findings. The primary endpoint was H. pylori infection rate according to the severity of erythematous/exudative gastritis (mild vs. moderate-to-severe). Results: A total of 177 patients with erythematous/exudative gastritis were included. The rate of H. pyloriinfection was 86.4% in all patients. Of 177 included patients, 78 were at mild degree, 48 were at moderate degree, and 51 were at severe degree. The inter-observer variation was 4.6% and kappa value was 0.593. H. pylori infection rate was similar between patients with mild erythematous/exudative gastritis and those with moderate-to-severe erythematous/exudative gastritis (91.0% vs. 82.8%, p=0.115). Even after adjusting potential confounding variables, the severity of erythematous/exudative gastritis was not associated with H. pylori infection rate. Conclusions H. pylori infection is commonly observed in patients with erythematous/exudative gastritis. However, the severity of erythematous/exudative gastritis is not associated with H. pylori infection rate.