AIMS: There has been limited information about the relations between Helicobacter pylori infection and expressions of apoptosis-related proteins p53, ASPP and iASPP in gastric cancer and precancerous lesions.METHODS: H. pylori in gastric mucosa were identified by W-S staining and rapid urease test. Expression of apoptosis-related proteins P53, ASPP2 and iASPP in the gastric tissues were determined by immunohistochemistry.RESULTS: The concentrations of H. pylori and expressions of p53 and iASPP in gastric carcinoma group and precancerous lesion group were higher than in benign gastric diseases group (P<0.05). The expressions of ASPP2 in gastric carcinoma and precancerous lesion group were lower than in benign gastric diseases group (P<0.05). The expressions of p53 and iASPP in H. pylori positive group were higher than in H. pylori negative group (P<0.05), whereas ASPP2 in H. pylori positive group were lower than in H. pylori negative group (P<0.05).CONCLUSION: There was a higher rate H. pylori infection, an increased expression of apoptosis inhibitor iASPP, and decreased expression of apoptosis stimulator ASPP2 in gastric cancer or precancerous tissues. These results suggest that H. pylori may cause gastric cancer by up-regulating iASPP and down-regulating ASPP2.