Background and Aim: Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs) are deeply involved in the etiology of gastric ulcers. The aim of our study was to clarify the endoscopic characteristics and H. pylori infection status of NSAID-associated gastric ulcers. Methods: The study group comprised 50 patients (23 men, 27 women; mean age 66.5 years) with NSAID-associated gastric ulcers and 100 sex- and age-matched patients with gastric ulcer associated with other factors (control group). Ulcer morphology, size and number of lesions, onset site and incidence of hemorrhagic ulcers were investigated endoscopically in both groups. H. pylori infection was diagnosed by serology, histology and C-13-urea breath test. Results: Multiple lesions (68% vs 20%, P < 0.001), occurrence in the antrum (56% vs 6%, P < 0.001), and hemorrhagic ulcer (34% vs 4%, P < 0.001) were significantly more prevalent in patients with NSAID-associated gastric ulcers than in patients with non-NSAID-associated gastric ulcer. The H. pylori infection rate was significantly lower in NSAID-associated gastric ulcer patients than in non-NSAID-associated gastric ulcer patients (48% vs 96%, P < 0.001). In the NSAID-associated gastric ulcer group, the prevalence of H. pylori infection was significantly lower in patients with ulcers in the antrum than in those with ulcers in the angulus or corpus (25% vs 77.3%, P < 0.001). Conclusions: In contrast to non-NSAID-associated gastric ulcers, NSAID-associated gastric ulcers frequently occur in the antrum with bleeding. The rate of H. pylori infection in NSAID-associated gastric ulcers is significantly lower than that in non-NSAID-associated gastric ulcers.