AIM: To compare the prevalence of H pylori infection,peptic ulcer, cytomegalovirus (CMV) infection and Candida esophagitis in human immunodeficiency virus (HIV)-positive and HIV-negative patients, and evaluate the impact of CD4 lymphocyte on H pylori and opportunistic infections.METHODS: A total of 151 patients (122 HIV-positive and 29 HIV-negative) with gastrointestinal symptoms were examined by upper endoscopy and biopsy. Samples were assessed to determine the prevalence of H pylori infection,CMV, candida esophagitis and histologic chronic gastritis.RESULTS: The prevalence of H pylori was less common in HIV-positive patients (22.1%) than in HIV-negative controls (44.8%; P ＜ 0.05), and the prevalence of H pylori displayed a direct correlation with CD4 count stratification in HIV-positive patients. In comparison with HIV-negative group, HIV-positive patients had a lower incidence of peptic ulcer (20.7% vs 4.1%; P ＜ 0.01), but a higher prevalence of chronic atrophy gastritis (6.9% vs 24.6%; P ＜ 0.05), Candida esophagitis and CMV infection. Unlike HIV-negative group, H pylori infection had a close relationship to chronic active gastritis (P＜0.05). In HIV-positive patients, chronic active gastritis was not significantly different between those with H pylori infection and those without.CONCLUSION: The lower prevalence of H pylori infection and peptic ulcer in HTV-positive patients with gastrointestinal symptoms suggests a different mechanism of peptic ulcerogenesis and a different role of H pylori infection in chronic active gastritis and peptic ulcer.The pathogen of chronic active gastritis in HIV-positive patients may be different from the general population that is closely related to H pylori infection.