Abstract: Objective To investigate the prevalence of Helicobacter pylori (Hp) infection in Chengdu and its risk factors. Methods Permanent residents in Chengdu who took routine health examinations in the West China Hospital of Sichuan University were recruited in the study. All participants received ¹⁴C-urea breath test (¹⁴C-UBT) for the diagnosis of Hp infection. A random sample (n=500) was drawn for a questionnaire survey. Results Of 8 365 participants, 53.1% were diagnosed with Hp infection. Higher prevalence was found in male participants (54.1%) than in female participants (51.7%,P<0.05). More than half of those older than 30 years old were infected. Of the 500 people who were invited to participate in the questionnaire survey, 497 returned questionnaires eligible for analyses. Compared with Han, Tibetans had a higher level of Hp infection (74.2% vs. 48.6%, P<0.05). Higher levels of Hp infection were also found in those with vomiting symptoms (63.4% vs. 52.2%, P<0.05). The participants who ate raw garlic had a lower level of Hp infection than those who did not eat raw garlic (52.6% vs. 67.9%, P<0.05). Conclusion The prevalence of Hp infection in Chengdu is high. Male, Tibetan and vomiting symptoms are predictors of Hp infection, while raw garlic seems to reduce the infection.