Purpose: Interest in peptic ulcer in children has been relatively low because the disease is rarer in children than in adults and there were restrictions in the application of endoscopy to children, but the recent development of pediatric endoscopy is activating research on pediatric peptic ulcer. Thus, this study compared the $H.$ $pylori$ infection rate and clinical and endoscopic findings among pediatric patients diagnosed with peptic ulcer. Methods: We analyzed retrospectively 58 pediatric patients for whom whether to be infected with $H.$ $pylori$ was confirmed selected out of pediatric patients diagnosed with gastric ulcer or duodenal ulcer through upper gastrointestinal endoscopy at the Department of Pediatrics of Gachon University Gil Hospital during the period from January 2002 to December 2007. A case was considered $H.$ $pylori$ positive if $H.$ $pylori$ was detected in the Giemsa stain of tissue or the results of UBT (urea breath test) and CLO (rapid urease test) were both positive. Results: Of the pediatric patients, 37 were infected with $H.$ $pylori$ and 21 were not. The $H.$ $pylori$ infection rate increased with aging and the result was statistically significant ($p$<0.05). However, $H.$ $pylori$ infection was not in a statistically significant correlation with sex, chief complaint, and gastroduodenal ulcer ($p$>0.05). Conclusion: $H.$ $pylori$ infection increased with aging, but was not significantly correlated with gastroduodenal ulcer. Further research may need to examine prospectively the relation between $H.$ $pylori$ and gastroduodenal ulcer in the Incheon area.