As CDX2 expression precedes the occurrence of gastric preneoplastic lesions in the intestinal differentiation pathway, study of these steps of gastric carcinogenesis may contribute toward understanding the early effects of gastric cancer determinants. Our aim was to quantify the association between Helicobacter pylori infection and other environmental factors and the gastric expression of CDX2. Dyspeptic patients undergoing an upper digestive endoscopy (Gastroenterology Department, Maputo Central Hospital) were consecutively invited to participate in this study and classified as having normal stomach/chronic nonatrophic gastritis (NS/CNAG), chronic atrophic gastritis (CAG), or intestinal metaplasia (IM). For all patients with CAG or IM and a subsample of NS/CNAG patients (sex-matched and age-matched, 1 : 2), H. pylori infection and CDX2 gene expression were assessed by histology and PCR and by immunohistochemistry, respectively. Age-adjusted, sex-adjusted, education-adjusted, and H. pylori infection-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were computed. CDX2 expression was observed in 56 NS/CNAG (49.1%), 39 CAG (86.7%), and all IM patients (n=12). It was more frequent among the H. pylori-infected patients (OR=2.26, 95% CI: 1.00-5.15). Infection with high-virulence strains was associated with CDX2 expression in patients with CAG (cagA, OR=3.20, 95% CI: 1.35-7.52) and IM (vacA m1, OR=5.86, 95% CI: 1.08-31.62). Patients with a lower frequency of vegetable consumption had a higher risk of marked CDX2 expression (OR=3.64, 95% CI: 1.02-12.95). The virulence of the infecting strains and vegetable consumption were associated with CDX2 expression and may play a role in the progression to more advanced lesions.