Objective: To investigate the effect of Helicobacter pylori (H. pylori)　on the synthesis of cyclooxygenase-1 (COX-1)　and cyclooxygenase-2 (COX-2) in gastric epithelial cells. Methods: a VacA(+) and CagA(+) international standard H. pylori line NCTC11637 and a human gastric epithelial carcinoma cell line BGC-823 were used. Western Blotting was applied to detect the synthesis of cyclooxygenase. Results: The content of COX-2 protein increased obviously after the cells were incubated with H. pylori sonicating extract for 1　h and the increase lasted for at least 6　h whereas the content of COX-1 protein did not change during the incubation with H. pylori extract. H. pylori lipopolysaccharide (LPS) had no effect on COX-2 synthesis. Conclusion: H. pylori stimulated the synthesis of COX-2 in BGC-823 cells and the effect was LPS-independent.