Abstract: Abstract Objective: To investigate the expression of HIF-1α and iNOS in Helicobacter pylori (Hp) -positively gastric adenocarcinoma (GAC). Methods: we collected 198 paraffin-embedded human GAC samples which have detailed follow-up and clinicopathologic data , meanwhile the 98 gastritis samples were collected as control group which divided into atrophic gastritis group and non-atrophic gastritis group.All of them have been accepted as c14 breath test to identify Hp infectious atatus. Using immunohistochemical staining to detect the expression of HIF-1a and iNOS. Results: Hp-positive infection was most frequently in GAC group than that of atrophic gastritis group and non- atrophic gastritis group (69.70%、59.62%和47.83%). The more positive expression of HIF-1a and iNOS can be seen in GAC group than that of atrophic gastritis group and non-atrophic gastritis group（P＜0．05）. The positive expression of HIF-1a and iNOS were higher in Hp+ GAC than in Hp- GAC.Conclusion: The carcinogenesis of Hp might be through the pathway of HIF-1a and iNOS.

Key words: Helicobacter pylori, stomach neoplasms, Hypoxia-inducible factor-1, Inducible nitric oxide synthase, Atrophic gastrtis